Integrated hydraulic cylinder test bench

Abstract

The invention discloses an integrated hydraulic cylinder test bench which comprises a test unit, an oil supply unit, an auxiliary unit and an electric control unit, the test unit is connected with the oil supply unit and the auxiliary unit, the test unit, the oil supply unit and the auxiliary unit are connected with the electric control unit, the oil supply unit provides pressure needed by testing for the test unit, and the auxiliary unit is connected with the electric control unit. The test unit is used for testing the oil pressure of a hydraulic cylinder and transmitting a pressure change signal in the hydraulic cylinder to the electric control unit, the electric control unit is used for controlling the electromagnetic valve to change the flowing direction of the oil in a test bed pipeline, and the auxiliary unit is used for filling high-pressure gas into the pipeline after the test is finished and discharging the oil back to an oil tank. The device has the advantages that oil is discharged and returned based on an air source, full-automatic continuous testing of the hydraulic cylinder is achieved, and therefore the testing efficiency of the hydraulic cylinder is improved.

Description

Technical Field

[0001] The present invention relates to the fields of wind turbine blade transportation and large-flow hydraulic technology, and in particular to an integrated hydraulic cylinder test bench. Background Art

[0002] Currently, high-flow hydraulic cylinders are the core actuators in hydraulic suspension systems, and their performance directly affects the performance of the entire system. In particular, the design of a hydraulic cylinder test bench is crucial for quality assurance of hydraulic cylinders in the hydraulic suspension systems of wind turbine transport vehicles. A hydraulic cylinder test bench is a device specifically designed to test the performance of hydraulic cylinders. According to the test items and methods for hydraulic cylinder product performance in GB / T15622-2005, "Hydraulic Cylinder Test Methods," the hydraulic cylinder test bench should be able to comprehensively test key performance indicators such as the hydraulic cylinder's starting pressure, pressure resistance, durability, and leakage. Therefore, hydraulic cylinder test bench testing prevents hydraulic cylinders with quality issues from entering the market, creating safety hazards and economic losses. A highly automated hydraulic cylinder test bench can reduce manual operations, improve testing efficiency, and minimize human error.

[0003] Existing hydraulic cylinder test benches have several shortcomings, including low automation, limited test items, low accuracy, and an inability to test multiple hydraulic cylinder types. These shortcomings lead to low testing efficiency and inaccurate test results. Among them, traditional test benches, due to manual adjustment of test parameters and a lack of sensor detection, are time-consuming and prone to misoperation, making high-precision control and data collection difficult to achieve.

[0004] In summary, there is at least one of the following technical problems: Low degree of automation, limited test items, low accuracy, and inability to perform simultaneous testing of multiple types and multiple hydraulic cylinders; Low testing efficiency and inaccurate test results; Manual adjustment of test parameters and lack of sensor detection are time-consuming and prone to misoperation, making it difficult to achieve high-precision control and data collection; The oil drainage and oil return efficiency is low, the oil drainage is not thorough, and the continuous testing efficiency is low; It is difficult to efficiently simulate the complete oil flow state test from the oil tank to the hydraulic cylinder. Summary of the Invention

[0005] The main purpose of the present invention is to provide an integrated hydraulic cylinder test bench to solve at least one technical problem in the existing technology, such as low degree of automation, limited test items, low precision and inability to realize detection of various types of hydraulic cylinders; low test efficiency and inaccurate test results; manual adjustment of test parameters and lack of sensor detection, which is time-consuming and prone to misoperation and difficult to achieve high-precision control and data acquisition; low oil drainage and oil return efficiency, incomplete oil drainage and low continuous testing efficiency; and difficulty in efficiently simulating at least one technical problem in the complete oil flow state test of the oil circuit from the oil tank to the hydraulic cylinder.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, an integrated hydraulic cylinder test bench is provided, comprising a test unit, an oil supply unit, an auxiliary unit and an electronic control unit, wherein the test unit is respectively connected to the oil supply unit and the auxiliary unit, and the test unit, the oil supply unit and the auxiliary unit are respectively connected to the electronic control unit, the oil supply unit provides the test unit with the pressure required for testing, the test unit is used to test the hydraulic cylinder oil pressure and transmit the pressure change signal in the hydraulic cylinder to the electronic control unit, the electronic control unit is used to control the solenoid valve to change the flow direction of the oil in the test bench pipeline, and the auxiliary unit is used to flush high-pressure gas into the pipeline after the test is completed and discharge the oil back to the oil tank.

[0007] Preferably, the oil supply unit includes a motor, which is connected to the hydraulic pump through a coupling, the hydraulic pump is connected to the oil suction filter, the oil suction filter is connected to the oil tank, the hydraulic pump is connected to the second three-position four-way electromagnetic reversing valve of the electronic control unit through a second one-way valve, the second three-position four-way electromagnetic reversing valve is connected to the flow meter, the flow meter is connected to the return oil filter, the return oil filter is connected to the oil tank, and an overflow valve is connected between the second one-way valve and the second three-position four-way electromagnetic reversing valve.

[0008] Preferably, the auxiliary unit includes an air source, the air source is connected to the pneumatic triplet, the pneumatic triplet is connected to the first one-way valve, the first one-way valve is connected to the three-position five-way electromagnetic reversing valve of the electronic control unit, the three-position five-way electromagnetic reversing valve is connected to the first muffler and the second muffler, the pneumatic triplet includes an air filter, a pressure reducing valve and an oil mist collector connected in series in sequence; the auxiliary unit also includes a temperature sensor, a first swing air motor, a second swing air motor, a first throttle valve and a second throttle valve, the temperature sensor is arranged in the oil tank, the first swing air motor, the second swing air motor, the first throttle valve and the second throttle valve are arranged on the air path connecting the auxiliary unit and the test unit.

[0009] Preferably, the test unit includes several test branches, each test branch is provided with a high-pressure ball valve, a quick connector, a pressure gauge, and a pressure sensor, wherein the high-pressure ball valve is connected to the quick connector, and a pressure sensor and a pressure gauge are also provided between the high-pressure ball valve and the quick connector. The quick connector is connected to the corresponding hydraulic cylinder, and a corresponding high-pressure ball valve and swing air motor combination is also provided between the test branch and the air circuit of the auxiliary unit. The swing air motor drives the high-pressure ball valve to rotate to realize pneumatic connection or locking of the oil circuit, and the test branches are arranged in pairs.

[0010] Preferably, the electronic control unit includes a PLC control system, a first three-position four-way solenoid reversing valve, a second three-position four-way solenoid reversing valve and a three-position five-way solenoid reversing valve. The pressure sensor of the test unit is used to monitor the pressure changes in the hydraulic cylinder and transmit the signal to the PLC control system. The PLC control system controls the switching of the first three-position four-way solenoid reversing valve, the second three-position four-way solenoid reversing valve and the three-position five-way solenoid reversing valve, and changes the flow direction of the oil in the test bench pipeline through the switching of the first three-position four-way solenoid reversing valve, the second three-position four-way solenoid reversing valve and the three-position five-way solenoid reversing valve.

[0011] Preferably, under no-load conditions, the electronic control unit controls the motor speed to slowly increase, and adjusts the system pressure to gradually increase until the hydraulic cylinder starts, thereby obtaining the minimum starting pressure of the hydraulic cylinder; by applying a constant pressure to the inside of the hydraulic cylinder and maintaining the pressure for a certain period of time, the pressure resistance data is obtained; during the test, the pressure change is monitored in real time by the pressure sensor and fed back to the PLC control system of the electronic control unit. If the pressure is lower than the set lower limit or higher than the set upper limit, the PLC control system controls to issue an alarm and take corresponding measures.

[0012] Preferably, the electronic control unit controls the oil supply unit to inject hydraulic oil into the hydraulic cylinder to a specified pressure value, and detects the pressure change within a certain period of time through the pressure sensor to test whether the piston is leaking.

[0013] Preferably, when the test is completed, the electronic control unit controls the four-way electromagnetic reversing valve to the left position, and the swing air motor rotates in the opposite direction, so that the branch oil circuit corresponding to the hydraulic cylinder inflation chamber is locked, and the branch oil circuit connected to the return oil chamber is connected. The electronic control unit controls the air source to pump gas into the hydraulic cylinder, pushing the piston to move, and draining the oil on the other side of the hydraulic cylinder piston back to the oil tank, completing the oil recovery and preparing for the next round of testing.

[0014] Preferably, the oil is discharged back to the oil tank through the air source, and the first swing air motor and the second swing air motor are controlled by the air source to further control the first high-pressure ball valve and the second high-pressure ball valve, thereby realizing gas-liquid linkage dual control.

[0015] Preferably, the PLC control system of the electronic control unit automatically records and saves the time-varying curve data of the pressure in the pipeline. The PLC control system realizes the test functions of automatically switching the inlet and outlet directions of the test bench, automatically locking the valve path, automatically switching the air path to discharge the oil inside the hydraulic cylinder, and automatically judging the sealing performance of the hydraulic cylinder based on the pressure curve data and a pre-written program.

[0016] The application of the technical solution of the present invention has the following technical effects: It has the function of integrated testing of the reciprocating operation state of the hydraulic cylinder and exhausting the air inside the hydraulic cylinder. Under no-load conditions, adjust the system pressure so that the pressure gradually increases to the point where the hydraulic cylinder starts, and test the minimum starting pressure of the hydraulic cylinder. Apply a fixed pressure to the inside of the hydraulic cylinder, maintain the pressure for a certain period of time, and test the pressure resistance. Inject hydraulic oil into the hydraulic cylinder to the specified pressure value, and use the system to detect the pressure change within a certain period of time to test whether the piston has internal leakage. By applying pressure to the inside of the hydraulic cylinder, check whether there is leakage at the static seals, joint surfaces and adjustable parts of the cylinder body. When the cylinder diameter is greater than 32mm and the minimum pressure is less than 0.5Mpa, reciprocate to test the low-pressure sealing. The hydraulic cylinder is operated to the extreme positions at both ends to test the technical effect of the stroke.

[0017] At the end of the test, the electronic control unit controls the three-position, five-way solenoid reversing valve. The gas output from the air source is processed by the pneumatic triplet (air filter, pressure reducing valve, and oil mist collector), then reaches the three-position, five-way solenoid reversing valve through the first one-way valve and is discharged through the first or second muffler. At the same time, the electronic control unit controls the four-way solenoid reversing valve to the left position, and the swing air motor rotates in the opposite direction, locking the branch oil circuit connected to the hydraulic cylinder's charging chamber and connecting the branch oil circuit connected to the oil return chamber. The air source pumps gas into the hydraulic cylinder, pushing the piston to move, and draining the oil on the other side of the hydraulic cylinder piston back to the tank, completing the oil recovery and preparing for the next round of complete oil circuit flow and pressure testing, thereby improving test efficiency.

[0018] The air source is used to drain the oil back to the oil tank, complete the oil recovery, prepare for the next round of complete oil circuit flow and pressure testing, improve the test efficiency, and use the air source to control the swing air motor to operate the high-pressure ball valve to achieve the effect of automatic control, that is: air source linkage control, the auxiliary unit not only realizes the automatic recovery of oil after the test through the air source, but also controls the swing air motor through the air source to control the switch of the high-pressure ball valve, realizing automatic control of oil circuit connection or locking, forming a dual application of air source in oil recovery and oil circuit control, simplifying the system structure and improving the reliability of control.

[0019] After the test, the air source flushes high-pressure gas into the pipeline, discharges the oil back to the oil tank, and prepares for the next batch of hydraulic cylinder tests. The swing air motor in the auxiliary unit is powered by the air source. When the air source inflates the hydraulic cylinder, the oil inlet pipeline of the oil supply unit is locked to quickly and efficiently drain the oil in the pipeline, simulating the test of the complete oil flow state from the oil tank to the hydraulic cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 A structural schematic diagram of an integrated hydraulic cylinder test bench according to the present invention is shown.

[0021] The above drawings include the following reference numerals: Air source 1; first muffler 2.1; second muffler 2.2; pneumatic triplex 3; 4, three-position five-way solenoid reversing valve 4; first throttle valve 5.1; second throttle valve 5.2; first high-pressure ball valve 6.1; second high-pressure ball valve 6.2; third high-pressure ball valve 6.3; fourth high-pressure ball valve 6.4; fifth high-pressure ball valve 6.5; sixth high-pressure ball valve 6.7; eighth high-pressure ball valve 6.8; first pressure gauge 71; second pressure gauge 7.2; third pressure gauge 7.3; fourth pressure gauge 7.4; fifth pressure gauge 7.5; sixth pressure gauge 7.6; seventh pressure gauge 7.7; first pressure sensor 8.1; second pressure sensor 8.2; third pressure sensor 8.3; Fourth pressure sensor 8.4; fifth pressure sensor 8.5; sixth pressure sensor 8.6; first quick connector 9.1; second quick connector 9.2; third quick connector 9.3; fourth quick connector 9.4; fifth quick connector 9.5; sixth quick connector 9.6; first swing air motor 10.1; second swing air motor 10.2; first three-position four-way solenoid reversing valve 11.1; second three-position four-way solenoid reversing valve 11.2; first one-way valve 12.1; second one-way valve 12.2; hydraulic pump 13; coupling 14; motor 15; overflow valve 16; oil suction filter 17; flowmeter 18; return oil filter 19; temperature sensor 20; oil tank 21. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] like Figure 1As shown, an embodiment of the present invention provides an integrated hydraulic cylinder test bench, including a test unit, an oil supply unit, an auxiliary unit and an electronic control unit, wherein the test unit is respectively connected to the oil supply unit and the auxiliary unit, and the test unit, the oil supply unit and the auxiliary unit are respectively connected to the electronic control unit, and the oil supply unit provides the test unit with the pressure required for the test, and the test unit is used to test the hydraulic cylinder oil pressure and transmit the pressure change signal in the hydraulic cylinder to the electronic control unit, and the electronic control unit is used to control the solenoid valve to change the flow direction of the oil in the test bench pipeline, and the auxiliary unit is used to flush high-pressure gas into the pipeline after the test is completed, and discharge the oil back to the oil tank 21.

[0024] In this embodiment, the oil supply unit includes a second one-way valve 12.2, a hydraulic pump 13, a coupling 14, a motor 15, a relief valve 16, an oil suction filter 17, a flowmeter 18, a return oil filter 19, a temperature sensor 20, and an oil tank 21. The motor 15 is connected to the hydraulic pump 13 via the coupling 14. The hydraulic pump 13 is connected to the oil suction filter 17, which is connected to the oil tank 21. The hydraulic pump 13 is connected to the second, three-position, four-way solenoid reversing valve 11.2 of the electronic control unit via the second one-way valve 12.2. The second, three-position, four-way solenoid reversing valve 11.2 is connected to the flowmeter 18, which is connected to the return oil filter 19, which is connected to the oil tank 21. The relief valve 16 is connected between the second one-way valve 12.2 and the second, three-position, four-way solenoid reversing valve 11.2. In the specific oil supply unit, motor 15 provides power, driving hydraulic pump 13 through coupling 14, serving as the power source for the oil supply unit. Coupling 14 connects motor 15 and hydraulic pump 13, transmitting power and ensuring coaxiality between them for smooth power transmission. Hydraulic pump 13 converts the mechanical energy of motor 15 into hydraulic energy, draws hydraulic oil from tank 21, and pressurizes it for delivery, providing the required oil pressure to the test unit. An oil suction filter 17, installed at the intake port of hydraulic pump 13, filters the hydraulic oil drawn from tank 21, preventing impurities from entering the pump 13 and protecting the pump and the entire hydraulic system. Tank 21 stores hydraulic oil, providing a reserve for the hydraulic system while also dissipating heat and settling impurities. A second check valve 12.2, installed between hydraulic pump 13 and second, three-position, four-way solenoid directional valve 11.2, prevents oil backflow and ensures that oil flows only from hydraulic pump 13 to the directional valve, protecting the pump 13. The second, three-position, four-way solenoid directional valve 11.2 is controlled by the electronic control unit to change the flow direction of the oil, thereby controlling the movement of the hydraulic cylinder and switching the oil flow direction during testing. A flowmeter 18 measures the oil flow through the pipeline, providing a basis for system flow control and test data analysis. A return oil filter 19 is installed on the oil return line to filter the oil returning to the oil tank 21, removing impurities and ensuring the cleanliness of the oil in the tank 21. A relief valve 16 is connected in parallel in the oil line between the second check valve 12.2 and the second, three-position, four-way solenoid directional valve 11.2. When the system pressure exceeds the set value, the relief valve 16 opens, allowing the oil to flow back to the tank 21, providing a safety protection measure to prevent excessive system pressure from damaging components. In this embodiment, the auxiliary unit includes an air source 1 connected to a pneumatic triplet 3, which is connected to a first one-way valve 12.1, which is connected to a three-position, five-way electromagnetic reversing valve 4 of the electronic control unit. The three-position, five-way electromagnetic reversing valve 4 is connected to a first muffler 2.1 and a second muffler 2.2. The pneumatic triplet 3 includes an air filter, a pressure reducing valve, and an oil mist collector connected in series. The auxiliary unit also includes a temperature sensor 20, a first oscillating air motor 10.1, a second oscillating air motor 10.2, a first throttle valve 5.1, and a second throttle valve 5.2. The temperature sensor 20 is located in an oil tank 21. The first and second oscillating air motors 10.1, 10.2, and the first and second throttle valves 5.1, 5.2 are located in the air path connecting the auxiliary unit and the test unit. Specifically, in the auxiliary unit, the air source 1 provides high-pressure gas, which serves as the auxiliary unit's power source. It is used to drain oil back to the oil tank 21 after testing and to drive the oscillating air motors. The pneumatic triplex 3 includes an air filter, a pressure reducing valve, and an oil mist collector. The air filter removes impurities from the air source 1 to ensure air cleanliness; the pressure reducing valve reduces the high-pressure air from the air source 1 to the stable pressure required by the system; and the oil mist collector injects lubricating oil into the air circuit to lubricate the pneumatic components and extend their service life. A first check valve 12.1 is installed between the pneumatic triplex 3 and the three-position, five-way electromagnetic reversing valve 4 to prevent gas backflow and ensure that gas can only flow from the pneumatic triplex 3 to the reversing valve. The three-position, five-way electromagnetic reversing valve 4 is controlled by the electronic control unit to change the direction of gas flow, controlling the direction of gas entering the swing air motor and thus the direction of rotation of the swing air motor. Excess gas is discharged through the connected first and second mufflers 2.1, 2.2, reducing noise. The first and second mufflers 2.1, 2.2 are installed on the three-position, five-way electromagnetic reversing valve 4 to reduce noise during gas discharge and minimize environmental impact. A temperature sensor 20 is installed in the oil tank 21 to monitor the temperature of the oil in the tank in real time, providing data support for the system's temperature control and fault diagnosis. The first and second oscillating air motors 10.1 and 10.2 are installed in the air path connecting the auxiliary unit and the test unit. Driven by the air source 1, they rotate, driving the high-pressure ball valve to connect or lock the oil path, thereby controlling the flow of oil. The first and second throttle valves 5.1 and 5.2 are installed in the air path connecting the auxiliary unit and the test unit to regulate the gas flow in the path and control the rotation speed of the oscillating air motors, ensuring smoother switching of the high-pressure ball valves.

[0025] In this embodiment, the test unit includes a first high-pressure ball valve 6.1, a second high-pressure ball valve 6.2, a third high-pressure ball valve 6.3, a fourth high-pressure ball valve 6.4, a fifth high-pressure ball valve 6.5, a sixth high-pressure ball valve 6.7, an eighth high-pressure ball valve 6.8, a first pressure gauge 7.1, a second pressure gauge 7.2, a third pressure gauge 7.3, a fourth pressure gauge 7.4, a fifth pressure gauge 7.5, a sixth pressure gauge 7.6, a seventh pressure gauge 7.7, a first pressure sensor 8.1, a second pressure sensor 8.2, a third pressure sensor 8.3, a fourth pressure sensor 8.4, a fifth pressure sensor 8.5, a sixth pressure sensor 8.6, a first quick connector 9.1, a second quick connector 9.2, a third quick connector 9.3, a fourth quick connector 9.4, a fifth quick connector 9.5, and a sixth quick connector 9.6. Each high-pressure ball valve is connected to a corresponding quick-connect coupling. A corresponding pressure gauge and pressure sensor are installed between the quick-connect coupling and the corresponding high-pressure ball valve. The quick-connect coupling is connected to the hydraulic cylinder under test, and the high-pressure ball valve is connected to a swing air motor. The swing air motor drives the high-pressure ball valve to rotate, connecting or locking the oil circuit. In the test unit, the high-pressure ball valve is connected to the hydraulic cylinder under test via a quick-connect coupling. Driven by the swing air motor, it rotates to connect or lock the oil circuit, controlling whether oil enters the hydraulic cylinder under test and whether the oil circuit is open or closed. The quick-connect coupling connects the high-pressure ball valve and the hydraulic cylinder under test, enabling quick installation and removal, improving testing efficiency, and ensuring a tight connection. A pressure gauge is installed between the quick-connect coupling and the high-pressure ball valve, visually displaying the oil pressure in the pipeline, allowing operators to observe pressure conditions in real time. A pressure sensor is also installed between the quick-connect coupling and the high-pressure ball valve, converting changes in oil pressure in the pipeline into electrical signals and transmitting them to the PLC control system of the electronic control unit, providing accurate data for pressure monitoring and control. The hydraulic cylinder under test is the test object. Through its connection to the test unit, it receives pressurized oil from the oil supply unit and undergoes various performance tests. In this embodiment, the electronic control unit includes a PLC control system, a first, third, and fourth-way solenoid directional control valve 11.1, a second, third, and fourth-way solenoid directional control valve 11.2, and a third, fifth-way solenoid directional control valve 4. The pressure sensor of the test unit is used to monitor pressure changes in the hydraulic cylinder and transmit signals to the PLC control system. The PLC control system controls the switching of the first, third, and fourth-way solenoid directional control valve 11.1, the second, third, and fourth-way solenoid directional control valve 11.2, and the third, fifth-way solenoid directional control valve 4. The switching of the first, third, and fourth-way solenoid directional control valve 11.1, the second, third, and fourth-way solenoid directional control valve 11.2, and the third, fifth-way solenoid directional control valve 4 changes the direction of oil flow in the test bench pipeline. Specifically, the PLC control system is the core of the electronic control unit. It receives signals from the test unit pressure sensors, processes and analyzes the data, and controls the switching of the first, third, and fourth-way solenoid directional control valve 11.1, the second, third, and fourth-way solenoid directional control valve 11.2, and the third, fifth-way solenoid directional control valve 4 according to a pre-programmed program, thereby achieving automated control of the test bench. Simultaneously, the system automatically records and saves the time-varying pressure curve data in the pipeline, and automatically determines test results such as the hydraulic cylinder's sealing performance based on this pressure curve data. The first, third, and fourth-way solenoid directional valves 11.1 and 11.2, controlled by the PLC control system, change the flow direction of the oil in the oil supply unit pipeline, thereby controlling the movement direction of the hydraulic cylinder and achieving automatic switching of oil inlet and outlet directions during testing. The third, fifth-way solenoid directional valve 4, also controlled by the PLC control system, changes the flow direction of the auxiliary unit's air circuit, controlling the swing air motor's rotation direction and the gas exhaust path, achieving automatic locking of the oil circuit and automatic oil recovery.

[0026] In this embodiment, under no-load conditions, the electronic control unit slowly increases the speed of motor 15, gradually raising the system pressure to the point where the hydraulic cylinder starts, thereby obtaining the minimum starting pressure for the hydraulic cylinder. A constant pressure is applied to the hydraulic cylinder and maintained for a specified period of time to obtain pressure data. During the test, a pressure sensor monitors pressure changes in real time and feeds feedback to the electronic control unit's PLC control system. If the pressure falls below a set lower limit or rises above a set upper limit, the PLC control system issues an alarm and takes appropriate measures. The electronic control unit controls the oil supply unit to inject hydraulic oil into the hydraulic cylinder to a specified pressure. The pressure sensor then detects pressure changes over a specified period of time to test for internal piston leakage. When the test is complete, the electronic control unit controls the first, third, and fourth-way solenoid reversing valve 11.1 to the left position, and the swing air motor rotates in the opposite direction, locking the branch oil circuit connected to the hydraulic cylinder's charging chamber and connecting the branch oil circuit connected to the oil return chamber. The electronic control unit then controls the air source 1 to pump air into the hydraulic cylinder, pushing the piston to move and draining the oil on the other side of the piston back to the oil tank 21, completing oil recovery and preparing for the next round of testing and simulating the complete hydraulic oil flow process. Oil is drained back to the oil tank 21 via air source 1, which then controls the swing air motor and, in turn, the high-pressure ball valve, achieving automatic control. The electronic control unit's PLC control system automatically records and stores the time-varying pressure curve data in the pipeline. Based on this pressure curve data and a pre-programmed program, the PLC control system automatically switches the oil inlet and outlet directions, automatically locks the valve path, automatically switches the air path to drain the oil from the hydraulic cylinder, and automatically determines the hydraulic cylinder's sealing performance.

[0027] Specifically, the present invention comprises an oil supply unit, a test unit, an auxiliary unit, and an electronic control unit. The oil supply unit provides the required testing pressure for the test bench. The test unit monitors the oil pressure in its branch pipeline. A pressure sensor monitors pressure changes within the hydraulic cylinder and transmits the signal to the PLC control system in the electronic control unit. After the test is completed, the air source 1 in the auxiliary unit injects high-pressure gas into the pipeline, draining the oil back into the oil tank 21 to prepare for the next batch of hydraulic cylinder tests. The oscillating air motor in the auxiliary unit, powered by the air source 1, locks the oil supply unit's oil inlet pipeline when the air source 1 fills the hydraulic cylinder. The PLC control system in the electronic control unit receives signals from the pressure sensor and automatically records and analyzes pressure data. The electronic control unit controls the solenoid reversing valve according to a preset program, switching the test bench's oil flow direction, rotating the high-pressure ball valve to open and close the valve, draining the oil from the hydraulic cylinder, and assessing the hydraulic cylinder's sealing performance. This hydraulic cylinder continuous testing test bench, based on the oil return function of the air source 1, enables fully automatic continuous testing of hydraulic cylinders, thereby improving hydraulic cylinder testing efficiency.

[0028] Specifically, the hydraulic pump 13, powered by a motor 15, pumps oil from the oil tank 21, which is then filtered through a filter to remove impurities. A relief valve 16 provides overflow protection for the hydraulic system. The oil supply unit provides test pressure for the hydraulic cylinder, with a three-position, four-way reversing valve switching the oil supply and return chambers. The test unit consists of several high-pressure ball valves, a pressure gauge, a pressure sensor, and quick-connect connectors. The pressure gauge allows direct observation of oil pressure in the pipeline. The pressure sensor converts the oil pressure into an electrical signal and transmits it to the PLC control system. The auxiliary unit consists of a temperature sensor 20, an oscillating air motor, an air source 1, a pneumatic triplex 3, and a throttle valve. The temperature sensor 20 detects the hydraulic system oil temperature. The oscillating air motor is controlled by air source 1. The air source 1 introduces air into the pipeline after the hydraulic cylinder test is completed. The pneumatic triplex 3 includes an air filter, a pressure reducing valve, and an oil mist collector to purify, stabilize, and lubricate the air supplied by air source 1. The throttle valve controls the air flow in the air circuit. The electronic control unit (ECU) consists of a PLC control system and a solenoid directional valve, ensuring the sequential execution of the test items designed for the test bench. The ECU features a pressure sensor in the test unit that monitors pressure changes in the hydraulic cylinder and transmits signals to the PLC control system. The PLC control system controls the reversal of the solenoid directional valve, thereby changing the direction of oil flow in the test bench pipeline. A swing air motor is connected to the high-pressure ball valve. Electrical signals from the PLC control system actuate the valve core of the three-position, five-way directional valve (4), which is powered by air source (1), ensuring flow and locking of the oil circuit. Air source (1) inflates and drains the hydraulic cylinder. The oil supply unit is directly connected to the solenoid directional valve, actuating the valve core to supply and return oil to the two oil circuits. One end of the test unit is connected to the swing air motor and high-pressure ball valve assembly, and the other end is connected to the hydraulic cylinder under test via a quick connector. Each two test units are connected to the oil inlet and outlet of one of the hydraulic cylinders under test. The PLC control system automatically records and stores the time-varying pressure curve data in the pipeline. Based on pressure curve data and pre-programmed procedures, the PLC control system automatically switches the oil inlet and outlet directions, locks the corresponding valve circuits, switches the air circuits to drain the oil from the hydraulic cylinder, and automatically determines the hydraulic cylinder's sealing performance. During the hydraulic cylinder test, the piston on either side of the hydraulic cylinder forms an oil supply chamber and an oil return chamber. After the test is complete, the oil supply circuit is locked, and the piston on either side of the hydraulic cylinder forms an air charging chamber and an oil return chamber.

[0029] Specifically, a flowmeter 18 records the return oil flow rate, and a pressure gauge in the test unit monitors the pipeline pressure. The air source 1 in the auxiliary unit drains the oil in the hydraulic cylinder and pipeline back to the oil tank 21 after testing is complete. The swing air motor in the auxiliary unit rotates the high-pressure ball valve to connect and lock the oil circuit. The pressure sensor in the electronic control unit monitors pressure changes in the hydraulic cylinder and transmits the signal to the PLC control system. The PLC control system in the electronic control unit controls the solenoid reversing valve, thereby changing the flow direction of the oil in the test bench pipeline. The relief valve 16 in the oil supply unit can be an electro-proportional relief valve to achieve active and continuous control of the oil pressure in the pipeline. A temperature sensor 20 in the oil supply unit monitors the hydraulic system oil temperature. A cooling fan and heating coil are also included, and the PLC controls the hydraulic system oil temperature within the range of room temperature to 90°C. A manual high-pressure ball valve is also provided in the test unit to manually control pipeline connection and locking. Every two test units in the test unit are connected to the oil inlet and outlet of the hydraulic cylinder under test.

[0030] In specific applications, this test bench invention can perform the following tests: testing the reciprocating operation of a hydraulic cylinder and purging air from within it. Under no-load conditions, the system pressure is adjusted and gradually increased to the minimum starting pressure for the hydraulic cylinder to test the cylinder's starting pressure. Pressure resistance is tested by applying 1.5 times the nominal pressure to the cylinder and maintaining it for 10 minutes. Hydraulic oil is injected into the cylinder to a specified pressure, and the system monitors the pressure change over time to test for internal piston leakage. Pressurizing the cylinder interior allows for leaks to be inspected at static seals, mating surfaces, and adjustable points. For cylinders larger than 32mm and with a minimum pressure below 0.5 MPa, low-pressure sealing is tested by reciprocating operation. The cylinder is operated to its extreme ends to test its stroke. Specifically, the test bench can perform the following tests on hydraulic cylinders: Under no-load conditions, the motor speed is slowly increased by 15 rpm to gradually increase the system pressure to the point where the cylinder reaches displacement, testing the cylinder's starting pressure. At this point, the swing motor high-pressure ball valve group (first swing motor 10.1, first high-pressure ball valve 6.1 or second swing motor 10.2, and eighth high-pressure ball valve 6.8) is connected. The manual high-pressure ball valves (first through sixth high-pressure ball valves 6.1 and 6.7) are also connected. The first, three-position, four-way solenoid reversing valve 11.1 is a directional valve that controls the air path. When the reversing valve is in the right position, the first and second swing motors 10.1 and 10.2 rotate in the same direction, causing the swing motor high-pressure ball valve groups to be connected or closed simultaneously. The connection or closing of the swing motor high-pressure ball valve group (first swing motor 10.1, first high-pressure ball valve 6.1 or second swing motor 10.2, and eighth high-pressure ball valve 6.8) is controlled by the three-position, five-way solenoid reversing valve 4. The solenoid valve core of the second, three-position, four-way solenoid reversing valve 11.2 moves left and right at a constant frequency to test the reciprocating operation of the hydraulic cylinder. For cylinders with a diameter greater than 32 mm and a minimum pressure below 0.5 MPa, reciprocating operation is used to test low-pressure sealing. By applying pressure to the hydraulic cylinder, check for leaks at the static seals, mating surfaces, and adjustable points. Operate the hydraulic cylinder to its end limits and measure the piston rod stroke. Inject hydraulic oil into the cylinder to the nominal pressure. Use pressure sensors to monitor pressure changes over a period of time to test for internal piston leakage. Given the nominal pressure of a specific hydraulic cylinder model, apply 1.5 times the nominal pressure to the cylinder and maintain pressure for 10 minutes to test the cylinder's pressure resistance. After the test is complete, when the first, third, and fourth-way solenoid directional valve 11.1 is in the left position, the first and second swing air motors 10.1 and 10.2 rotate in opposite directions. At this point, one set of the swing air motor high-pressure ball valves is connected, while the other is locked. The branch oil circuit connected to the hydraulic cylinder's charge chamber is locked, and the branch oil circuit connected to the hydraulic cylinder's return oil chamber is connected. Air source 1 pumps air into the hydraulic cylinder, pushing the piston and discharging the oil on the other side of the piston back to tank 21. The hydraulic cylinder test is complete.More specifically, the test bench is designed for a maximum test pressure of 60 MPa and a maximum flow rate of 45 L / min. The hydraulic pump 13, motor 15, and relief valve 16 in the oil supply unit are selected as required. The oil tank 21 is equipped with a cooling fan and heating coil, and a PLC controls the test bench's hydraulic system oil temperature within a range from room temperature to 90°C. The hydraulic cylinder test bench uses No. 46 anti-wear hydraulic oil as the test fluid. The test bench can measure hydraulic cylinder diameters ranging from 20 mm to 800 mm.

[0031] Specifically, motor 15 is connected to hydraulic pump 13 via coupling 14. Motor 15 drives the pump blades to rotate, providing power. Oil in tank 21 is drawn from hydraulic pump 13, filtered through a suction filter to remove impurities, and then enters the test unit through a three-position, four-way solenoid directional valve. After the current batch of hydraulic cylinders is tested, the PLC controls the valve core of three-position, five-way solenoid directional valve 4 in the auxiliary unit, causing air source 1 to inflate the pipeline and discharge the oil. The oil then passes through the three-position, four-way solenoid directional valve and returns to the oil supply unit. After filtering impurities through a return filter, it returns to tank 21. In the test unit, each swing air motor drives the corresponding high-pressure ball valve to control the flow and locking of the corresponding oil pipeline branch. In the test unit, a pressure sensor transmits the pressure signal in the hydraulic cylinder to the PLC control system. Quick connectors connect the test unit to the hydraulic cylinder's inlet and outlet ports. For a dual-port hydraulic cylinder, each two test units are connected to the oil inlet and outlet of a test unit.

[0032] The present invention uses the air source 1 to discharge oil back to the oil tank 21, controls the swing air motor and further controls the high-pressure ball valve, thereby realizing automatic control and improving the test efficiency.

[0033] In this embodiment, when the oil supply unit is operating, motor 15 drives hydraulic pump 13 via coupling 14. Hydraulic pump 13 draws hydraulic oil from oil tank 21 through suction filter 17, pressurizes it, and discharges it through second one-way valve 12.2. Between second one-way valve 12.2 and second three-position four-way solenoid directional valve 11.2, relief valve 16 serves as a safety feature to prevent excessive system pressure. The pressurized oil flows back to oil tank 21 through second three-position four-way solenoid directional valve 11.2, flowmeter 18, and return filter 19, forming an oil supply circuit. The electronic control unit controls the direction of second three-position four-way solenoid directional valve 11.2, changing the direction of oil flow and providing pressurized oil to the test unit in different directions. In this embodiment, the test unit is working, the high-pressure ball valve is connected to the hydraulic cylinder to be tested through a quick connector, and the pressure gauge and pressure sensor between the quick connector and the high-pressure ball valve monitor the oil pressure in the pipeline in real time. Under no-load conditions, the electronic control unit controls the speed of the motor 15 to slowly increase, and the system pressure gradually increases. When the hydraulic cylinder starts, the pressure sensor transmits a signal to the electronic control unit to obtain the minimum starting pressure of the hydraulic cylinder. A fixed pressure is applied to the inside of the hydraulic cylinder and maintained for a certain period of time. The pressure sensor monitors the pressure changes in real time and obtains the pressure resistance data. If the pressure is lower than the set lower limit or higher than the set upper limit, the electronic control unit will sound an alarm and take corresponding measures. At the same time, the electronic control unit controls the oil supply unit to inject hydraulic oil into the hydraulic cylinder to the specified pressure value, and detects the pressure changes within a certain period of time through the pressure sensor to test whether the piston is leaking. In this embodiment, the auxiliary unit is operational. At the end of the test, the electronic control unit controls the three-position, five-way solenoid directional valve 4. Gas output from the air source 1 is processed by the pneumatic triplex 3 (air filter, pressure reducing valve, and oil mist collector) before passing through the first check valve 12.1 and reaching the three-position, five-way solenoid directional valve 4. It is then discharged through the first muffler 2.1 or the second muffler 2.2. Simultaneously, the electronic control unit controls the first three-position, four-way solenoid directional valve 11.1 to the left position. The swing air motor rotates in the opposite direction, locking the branch oil circuit connected to the hydraulic cylinder's charging chamber and connecting the branch oil circuit connected to the oil return chamber. Air source 1 pumps gas into the hydraulic cylinder, pushing the piston and draining the oil on the other side of the piston back to the oil tank 21. This completes oil recovery and prepares for the next round of complete oil circuit flow and pressure testing, improving test efficiency. The swing air motor drives the high-pressure ball valve to rotate, connecting or locking the oil circuit. The throttle valve regulates the gas flow in the circuit, and the temperature sensor 20 monitors the oil temperature in the oil tank 21. In this embodiment, the electronic control unit (ECU) controls the PLC control system, which receives pressure change signals from the test unit's pressure sensor and controls the first, third, fourth-way solenoid directional valve (11.1), the second, third, fourth-way solenoid directional valve (11.2), and the third, fifth-way solenoid directional valve (4), thereby changing the flow direction of oil and gas in the test bench's pipelines. Simultaneously, the PLC control system automatically records and stores the time-varying pressure curve data in the pipelines. Based on pre-programmed functions, the test bench automatically switches oil inlet and outlet directions, automatically locks valve paths, automatically switches air paths to drain oil from hydraulic cylinders, and automatically determines the hydraulic cylinder's sealing performance.

[0034] In this embodiment, through integrated design, the test unit, oil supply unit, auxiliary unit and electronic control unit are integrated into one, and the units work closely together to achieve the integration of hydraulic cylinder testing, pressure control, oil recovery and other functions. The structure is compact and the footprint is small, which improves the practicality and portability of the equipment. In this embodiment, fully automated control of the test bench is achieved through automated control, using the PLC control system of the electronic control unit. This includes functions such as automatically switching the oil inlet and outlet directions, automatically locking the valve path, automatically switching the air path to drain the oil inside the hydraulic cylinder, and automatically determining the sealing performance of the hydraulic cylinder. This reduces manual intervention, improves test efficiency and accuracy, and reduces human error.

[0035] In this embodiment, through the linkage control of the air source 1, the auxiliary unit not only realizes the automatic recovery of the oil after the test is completed through the air source 1, but also controls the swing air motor through the air source 1 and then controls the switch of the high-pressure ball valve, thereby realizing automatic control of the oil circuit connection or locking, forming a dual application of the air source 1 in oil recovery and oil circuit control, simplifying the system structure and improving the reliability of control. In this embodiment, it has comprehensive testing functions and can complete the detection of multiple key performance indicators such as the hydraulic cylinder minimum starting pressure test, pressure resistance test, internal leakage test, etc. The pressure sensor monitors the pressure changes in real time and feeds back to the PLC control system, realizing a comprehensive evaluation of the hydraulic cylinder performance and meeting the testing requirements under different working conditions. In this embodiment, through data processing and recording, the PLC control system automatically records and saves the time-varying curve data of the pressure in the pipeline, providing rich historical data for the performance analysis and quality evaluation of the hydraulic cylinder, facilitating subsequent tracing and optimization, and improving the scientificity and reliability of the test results.

[0036] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: It has the function of integrated testing of the reciprocating operation state of the hydraulic cylinder and exhausting the air inside the hydraulic cylinder. Under no-load conditions, adjust the system pressure so that the pressure gradually increases to the point where the hydraulic cylinder starts, and test the minimum starting pressure of the hydraulic cylinder. Apply a fixed pressure to the inside of the hydraulic cylinder, maintain the pressure for a certain period of time, and test the pressure resistance. Inject hydraulic oil into the hydraulic cylinder to the specified pressure value, and use the system to detect the pressure change within a certain period of time to test whether the piston has internal leakage. By applying pressure to the inside of the hydraulic cylinder, check whether there is leakage at the static seals, joint surfaces and adjustable parts of the cylinder body. When the cylinder diameter is greater than 32mm and the minimum pressure is less than 0.5Mpa, reciprocate to test the low-pressure sealing. The hydraulic cylinder is operated to the extreme positions at both ends to test the technical effect of the stroke.

[0037] At the end of the test, the electronic control unit controls the three-position, five-way solenoid directional valve 4. After being processed by the pneumatic triplex 3 (air filter, pressure reducing valve, and oil mist collector), the gas output from air source 1 passes through the first check valve 12.1 and reaches the three-position, five-way solenoid directional valve 4. It is then discharged through the first muffler 2.1 or the second muffler 2.2. Simultaneously, the electronic control unit controls the first three-position, four-way solenoid directional valve 11.1 to the left position, reversing the rotation of the swing air motor. This locks the branch oil circuit connected to the hydraulic cylinder's charging chamber and connects the branch oil circuit connected to the oil return chamber. Air source 1 pumps air into the hydraulic cylinder, pushing the piston and draining the oil on the other side of the piston back to the oil tank 21. This completes the oil recovery process and prepares for the next round of complete oil circuit flow and pressure testing. This fully simulates the flow of hydraulic oil from the cylinder to the oil circuit, improving test efficiency.

[0038] The operation of draining oil back to the oil tank 21 is realized through the air source 1, completing the oil recovery and preparing for the next round of complete oil circuit flow and pressure testing. The complete flow state simulation test of the hydraulic oil from the cylinder to the oil circuit is fully simulated to improve the test efficiency, and the air source 1 is used to control the swing air motor to operate the high-pressure ball valve to achieve the effect of automatic control, that is: the air source 1 is linked controlled, and the auxiliary unit not only realizes the automatic recovery of the oil after the test through the air source 1, but also controls the swing air motor through the air source 1 to control the switch of the high-pressure ball valve, realizing automatic control of the oil circuit connection or locking, forming a dual application of the air source 1 in oil recovery and oil circuit control, simplifying the system structure and improving the reliability of control. After the test, the air source 1 injects high-pressure gas into the pipeline and discharges the oil back to the oil tank 21 to prepare for the next batch of hydraulic cylinder tests. The swing air motor in the auxiliary unit is powered by the air source 1. When the air source 1 inflates the hydraulic cylinder, the oil inlet pipeline of the oil supply unit is locked to quickly and efficiently drain the oil in the pipeline, simulating the test of the complete oil flow state from the oil tank 21 to the hydraulic cylinder.

[0039] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An integrated hydraulic cylinder test bench, characterized in that: It includes a test unit, an oil supply unit, an auxiliary unit and an electronic control unit. The test unit is respectively connected to the oil supply unit and the auxiliary unit. The test unit, the oil supply unit and the auxiliary unit are respectively connected to the electronic control unit. The oil supply unit provides the test unit with the pressure required for testing. The test unit is used to test the oil pressure of the hydraulic cylinder and transmit the pressure change signal in the hydraulic cylinder to the electronic control unit. The electronic control unit is used to control the solenoid valve to change the flow direction of the oil in the test bench pipeline. The auxiliary unit is used to flush high-pressure gas into the pipeline after the test is completed and discharge the oil back to the oil tank.

2. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: The oil supply unit includes a motor, which is connected to a hydraulic pump through a coupling, the hydraulic pump is connected to an oil suction filter, the oil suction filter is connected to an oil tank, the hydraulic pump is connected to a second three-position four-way electromagnetic reversing valve of an electronic control unit through a second one-way valve, the second three-position four-way electromagnetic reversing valve is connected to a flow meter, the flow meter is connected to a return oil filter, the return oil filter is connected to an oil tank, and an overflow valve is connected between the second one-way valve and the second three-position four-way electromagnetic reversing valve.

3. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: The auxiliary unit includes an air source, which is connected to a pneumatic triplet, which is connected to a first one-way valve, which is connected to a three-position five-way electromagnetic reversing valve of an electronic control unit, which is connected to a first muffler and a second muffler, and the pneumatic triplet includes an air filter, a pressure reducing valve and an oil mist collector connected in series in sequence; the auxiliary unit also includes a temperature sensor, a first swing air motor, a second swing air motor, a first throttle valve and a second throttle valve, the temperature sensor is arranged in an oil tank, and the first swing air motor, the second swing air motor, the first throttle valve and the second throttle valve are arranged on the air path connecting the auxiliary unit and the test unit.

4. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: The test unit includes several test branches, each of which is provided with a high-pressure ball valve, a quick connector, a pressure gauge, and a pressure sensor. The high-pressure ball valve is connected to the quick connector, and a pressure sensor and a pressure gauge are also provided between the high-pressure ball valve and the quick connector. The quick connector is connected to the corresponding hydraulic cylinder. A corresponding high-pressure ball valve and a swing air motor combination is also provided between the test branch and the air circuit of the auxiliary unit. The swing air motor drives the high-pressure ball valve to rotate to achieve pneumatic connection or locking of the oil circuit. The test branches are arranged in pairs.

5. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: The electronic control unit includes a PLC control system, a first three-position four-way solenoid reversing valve, a second three-position four-way solenoid reversing valve and a three-position five-way solenoid reversing valve. The pressure sensor of the test unit is used to monitor the pressure changes in the hydraulic cylinder and transmit the signal to the PLC control system. The PLC control system controls the switching of the first three-position four-way solenoid reversing valve, the second three-position four-way solenoid reversing valve and the three-position five-way solenoid reversing valve. The flow direction of the oil and airflow in the test bench pipeline is changed by the switching of the first three-position four-way solenoid reversing valve, the second three-position four-way solenoid reversing valve and the three-position five-way solenoid reversing valve.

6. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: Under no-load conditions, the electronic control unit slowly increases the motor speed and adjusts the system pressure to gradually increase until the hydraulic cylinder starts, thereby obtaining the minimum starting pressure of the hydraulic cylinder. By applying a constant pressure to the inside of the hydraulic cylinder and maintaining the pressure for a certain period of time, the pressure resistance data is obtained. During the test, the pressure sensor monitors the pressure changes in real time and feeds back to the PLC control system of the electronic control unit. If the pressure is lower than the set lower limit or higher than the set upper limit, the PLC control system will issue an alarm and take corresponding measures.

7. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: The electronic control unit controls the oil supply unit to inject hydraulic oil into the hydraulic cylinder to a specified pressure value, and detects the pressure change within a certain period of time through the pressure sensor to test whether the piston has internal leakage.

8. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: When the test is completed, the electronic control unit controls the four-way electromagnetic reversing valve to the left position, and the swing air motor rotates in the opposite direction, so that the branch oil circuit corresponding to the hydraulic cylinder inflation chamber is locked, and the branch oil circuit connected to the return oil chamber is connected. The electronic control unit controls the air source to pump gas into the hydraulic cylinder, pushing the piston to move, and draining the oil on the other side of the hydraulic cylinder piston back to the oil tank, completing the oil recovery and preparing for the next round of testing.

9. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: The oil is discharged back to the oil tank through the air source, and the first swing air motor and the second swing air motor are controlled by the air source to further control the first high-pressure ball valve and the second high-pressure ball valve, thereby realizing gas-liquid linkage dual control.

10. The integrated hydraulic cylinder test bench according to claim 1, characterized in that: The PLC control system of the electronic control unit automatically records and saves the time-varying curve data of the pressure in the pipeline. The PLC control system realizes the test functions of automatically switching the inlet and outlet directions of the test bench, automatically locking the valve path, automatically switching the air path to discharge the oil inside the hydraulic cylinder, and automatically judging the sealing performance of the hydraulic cylinder based on the pressure curve data and a pre-written program.

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