A hydraulic cylinder leakage detection device and method

Abstract

The present application relates to the field of hydraulic system oil leakage detection, and particularly relates to a hydraulic cylinder leakage detection device and method. The device comprises a base body, an access element, a leakage feedback cylinder, a feedback module, a throttling module, a switching module, a reversing module and a control system. The present application can reflect the leakage condition in the form of numerical values, accurately feedback the severity of the leakage, and dataize the leakage condition, which is helpful for the state control of the measured cylinder in the whole life cycle, so that the maintenance process is not blind. Furthermore, the present application can accurately feedback the leakage condition which cannot be observed by naked eyes. Meanwhile, the present application can realize the automatic detection process, and the skill requirement of the hydraulic system maintenance personnel is not high. In addition, the present application does not cause oil waste or environmental pollution during the leakage detection. The implementer can construct the equipment architecture device according to the existing conditions and budget.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system oil leakage detection, and specifically to a hydraulic cylinder leakage detection device and method. Background Technology

[0002] A hydraulic system consists of five parts: power components, control components, auxiliary components, actuators, and hydraulic oil. Hydraulic oil, as the energy transfer medium, first converts mechanical energy into pressure energy through a hydraulic pump, then drives actuators such as hydraulic cylinders and hydraulic motors, thus realizing the conversion of pressure energy into mechanical energy. In a hydraulic system, P is the inlet port, T is the return port, and A and B are the inlet or return ports of the hydraulic actuator (hydraulic cylinder). The cylinder being tested has two chambers; the chamber containing the piston rod is called the rod chamber, and the chamber without the piston rod is called the plug chamber.

[0003] However, as a liquid fluid, hydraulic oil inherently presents leakage problems, which have always been a challenge in the use of hydraulic systems. Especially under high system pressures, leakage cannot be completely avoided. Hydraulic cylinders are among the most widely used actuators in hydraulic systems, and many leakage problems originate from them, causing significant difficulties in production and maintenance. Leakage in hydraulic cylinders mainly manifests in two forms: external leakage and internal leakage.

[0004] Hydraulic systems exhibit both internal and external leakage. Internal leakage refers to the flow of hydraulic oil from high-pressure areas to low-pressure areas caused by the aging and wear of sealing elements, while external leakage refers to the leakage of hydraulic oil from hydraulic components into the environment. Both imply a decline in component performance; the former directly affects the system's working capacity, while the latter also leads to hydraulic oil consumption and environmental pollution. The former occurs internally and cannot be directly observed, making maintenance and diagnosis difficult. The latter can be directly observed, but in wet machining centers using cutting oil as the medium, the hydraulic oil leaking from the clamping cylinders of the fixtures mixes with the cutting oil, thus still complicating maintenance and diagnosis.

[0005] To address the aforementioned problems, this invention is proposed. Summary of the Invention

[0006] To address the aforementioned problems, this invention is proposed. The technical solution is as follows: a hydraulic cylinder leakage detection device and method.

[0007] The technical solution is as follows:

[0008] A hydraulic cylinder leakage detection device is located between the hydraulic oil supply circuit and the cylinder under test. The hydraulic oil supply circuit is equipped with a cylinder directional control valve.

[0009] The base serves as a component carrier for the hydraulic cylinder leakage detection module. The base has internal hydraulic circuits for connecting various control valves, cylinders, and external interfaces.

[0010] The connector is used to connect the hydraulic cylinder leakage detection device between the tested cylinder and the cylinder directional control valve.

[0011] A leakage feedback cylinder is used to detect piston displacement when a leak occurs, and the control system calculates and reflects the distance the piston moves.

[0012] The feedback module is used to measure the movement of the piston in the leakage feedback cylinder and send the movement to the control system.

[0013] The throttling module is used to perform venting of the leakage feedback cylinder;

[0014] The switch module is used to control the exhaust of the leakage feedback cylinder chamber;

[0015] The reversing module is used to control the action sequence of each valve and to detect the leakage status of the tested cylinder.

[0016] The control system is used for controlling various modules and transmitting and receiving signals.

[0017] Furthermore, the connection element is a quick-connect plug or a hydraulic hose.

[0018] Furthermore, the reversing module and / or the switching module are manual and / or electric valves.

[0019] Furthermore, the reversing module includes a first electromagnetic reversing valve and a second electromagnetic reversing valve, which are in the form of superimposed valves and fixed to the base. The electromagnet of the electromagnet is connected to the control system, and the control system provides power to control the electromagnet. Both the first electromagnetic reversing valve and the second electromagnetic reversing valve are three-position four-way reversing valves.

[0020] Furthermore, the switching module used to control the exhaust of the leakage feedback cylinder chamber is a ball-seat valve for electromagnetic switching.

[0021] Furthermore, the first and second electromagnetic switch valves included in the switch module are cartridge valves, which are screwed into the base body by the threads on the valve body and fixed to the base body. Their electromagnets are connected to the control system, and the control system provides power to control the electromagnets.

[0022] Furthermore, the throttling module is an adjustable throttling valve and / or throttling port.

[0023] Furthermore, the throttling module includes a first throttling port and a second throttling port. The two throttling ports are two internal hexagonal set screws with holes in the center, which are tightened inside the base to create a change in the orifice diameter between the internal hydraulic oil passages, thereby controlling the flow of hydraulic oil.

[0024] Furthermore, the feedback module is a mechanical displacement measuring element and / or an analog sensor.

[0025] Furthermore, the feedback module includes a first analog sensor and the first analog sensor being fixed to the base by a sensor bracket and fixing bolts, connected to the control system, and inputting analog signals to the control system.

[0026] Furthermore, the reversing module includes a first two-position four-way reversing valve and a second two-position four-way reversing valve. The first two-position four-way reversing valve is a p-type side position with P for A and T for B; the second two-position four-way reversing valve is a p-type side position with P for B and T for A.

[0027] Furthermore, the leakage feedback cylinder includes a first leakage feedback cylinder and a second leakage feedback cylinder. The leakage feedback cylinder uses the base as its cylinder body. Each leakage feedback cylinder includes a piston, with a chamber at each end. A chamber spring is located within each chamber, and an end cap is located at the chamber opening. One end of the chamber spring abuts against the end cap, and the other end abuts against the piston. The piston of the leakage feedback cylinder is located inside the base. A sensing iron is mounted on the piston, and the sensing iron is adapted to the analog signal sensor. The piston drives the sensing iron to move, thereby changing the analog input value of the analog signal sensor. The analog signal sensor… The metal sensing block is threadedly installed in the middle position of the piston and can move with the piston, causing the value fed back to the control system by the analog sensor to change. Through the calculation of the control system, the control system can determine the position state of the piston. The left chamber spring and the right chamber spring at both ends of the piston are used to keep the piston in the middle position. Before leakage detection and during the detection preparation process, the oil pressure at both ends of the piston is zero or equal. The chamber springs on both sides can reset the piston to the middle position to initialize the analog sensor and ensure that the piston has a margin for left and right movement during the subsequent detection process.

[0028] Furthermore, both the piston and the end cap use combined Glyd ring seals.

[0029] Furthermore, the solenoid switch valve used to control the exhaust of the leakage feedback cylinder chamber is a ball seat valve.

[0030] Furthermore, the first and second electromagnetic directional valves are three-position four-way P-type valves, and the cylinder directional control valve is a three-position four-way O-type valve, a three-position four-way H-type valve, or a two-position four-way valve. The inlet of the hydraulic cylinder leakage detection device is connected to the P-path of the first electromagnetic directional valve. The A-port of the first electromagnetic directional valve is connected to the inlet of the left chamber of the first leakage feedback cylinder. The outlet of the left chamber of the first leakage feedback cylinder is connected to the inlet of the first switching valve. The outlet of the first switching valve is connected to the working port B of the first oil circuit via the first throttle port and is connected to the rod chamber of the cylinder under test. The B-port of the first electromagnetic directional valve is connected to the inlet of the right chamber of the first leakage feedback cylinder. The oil outlet of the right chamber of the first leakage feedback cylinder is connected to the working oil port A of the second oil circuit and the plug chamber of the cylinder under test; the return oil port of the hydraulic cylinder leakage detection device is connected to the second electromagnetic directional valve P circuit, the A port of the second electromagnetic directional valve is connected to the inlet of the left chamber of the second leakage feedback cylinder, and the oil outlet of the left chamber of the second leakage feedback cylinder is connected to the first oil circuit to the working oil port B; the B port of the second electromagnetic directional valve is connected to the inlet of the right chamber of the second leakage feedback cylinder; the oil outlet of the right chamber of the second leakage feedback cylinder is connected to the inlet of the second switching valve, and the oil outlet of the second switching valve is connected to the second oil circuit to the working oil port A via the second throttle port.

[0031] A method for detecting leakage in a hydraulic cylinder, comprising the following steps:

[0032] Part One:

[0033] 1) The pressure built up in the piston cavity of the tested hydraulic cylinder;

[0034] 2) Expel the air from the leak feedback cylinder chamber;

[0035] 3) Make the first leakage feedback cylinder the necessary channel for oil to enter the plug chamber of the cylinder under test, and make the second leakage feedback cylinder the necessary channel for oil to exit the rod chamber of the cylinder under test.

[0036] 4) Check for external leaks at the oil pipe, joint, and end cap on the piston side of the cylinder, and for internal leaks of the hydraulic oil in the piston chamber flowing from the piston to the rod chamber.

[0037] Part Two

[0038] 5) Pressure build-up in the rod chamber of the tested cylinder;

[0039] 6) Release the air from the leak feedback cylinder chamber;

[0040] 7) Make the second leakage feedback cylinder the necessary channel for oil inlet to the rod chamber of the cylinder under test, and make the first leakage feedback cylinder the necessary channel for oil outlet to the plug chamber of the cylinder under test.

[0041] 8) Check for external leaks at the oil pipe, joint, and end cap on the rod chamber side of the hydraulic cylinder, and check for internal leaks of hydraulic oil in the rod chamber that flow through the piston to the piston chamber.

[0042] Furthermore, the determination method for step 4 is as follows:

[0043] 1) When there is external leakage in the piston chamber of the tested cylinder, the piston of the first leakage feedback cylinder will move to the right. At this time, the first analog sensor will sense the movement of the piston and feed back the movement distance ΔS1 to the control system; the piston of the second leakage feedback cylinder will remain stationary, and the value ΔS2 fed back by the second analog sensor will not change. Therefore, in this case, ΔS1>0, ΔS2=0;

[0044] 2) When there is internal leakage from the piston chamber to the rod chamber in the tested cylinder, the piston of the first leakage feedback cylinder will move to the right, and the piston of the second leakage feedback cylinder will also move to the right. Both the first analog sensor and the second analog sensor will detect the movement of the pistons of the leakage feedback cylinders and feed back the movement distance to the control system. At this time, ΔS1=ΔS2>0;

[0045] 3) When the tested cylinder has both external leakage from the plug chamber and internal leakage from the plug chamber to the rod chamber, the piston of the first leakage feedback cylinder will move to the right, and the piston of the second leakage feedback cylinder will also move to the right. At this time, both the first analog sensor and the second analog sensor will detect the movement of the pistons of the leakage feedback cylinders and feed back the movement distance to the control system. In this case, ΔS1>ΔS2>0.

[0046] Furthermore, the determination method for step 8 is as follows:

[0047] 1) When there is an external leakage in the cylinder rod chamber under test, the piston of the second leakage feedback cylinder will move to the left. At this time, the second analog sensor will sense the movement of the piston and feed back the movement distance ΔS2 to the control system; the piston of the first leakage feedback cylinder will remain stationary, and the value fed back by the first analog sensor will not change ΔS1=0. At this moment, ΔS2>0, ΔS1=0.

[0048] 2) When there is internal leakage from the rod chamber to the plug chamber in the tested cylinder, the piston of the second leakage feedback cylinder will move to the left, and the piston of the first leakage feedback cylinder will also move to the left. At this time, both analog sensors will sense the movement of the piston of the leakage feedback cylinder and feed back the movement distance to the control system. At this moment, ΔS2=ΔS1>0.

[0049] 3) When the tested cylinder has both external leakage from the rod chamber and internal leakage from the rod chamber to the plug chamber, the piston of the second leakage feedback cylinder will move to the left, and the piston of the first leakage feedback cylinder will also move to the left. At this time, both the second analog sensor 10 and the first analog sensor 9 will sense the movement of the piston of the leakage feedback cylinder and feed back the movement distance to the control system. At this moment, ΔS2>ΔS1>0.

[0050] Furthermore, the mechanical displacement measuring element is a dial indicator, and the determination method in step 4 is as follows:

[0051] 1) When there is external leakage in the piston chamber of the tested cylinder, the piston of the first leakage feedback cylinder will move to the right, and the reading of dial indicator G1 will increase by ΔG1; the piston of the second leakage feedback cylinder will remain stationary, and the reading of dial indicator G2 will not change. Therefore, in this case, ΔG1>0, ΔG2=0;

[0052] 2) When there is internal leakage from the piston chamber to the rod chamber in the tested cylinder, the piston of the first leakage feedback cylinder will move to the right, and the piston of the second leakage feedback cylinder will also move to the right. At this time, the readings of dial indicators G1 and G2 will both increase. Furthermore, in this case, ΔG1 = ΔG2 > 0.

[0053] 3) When the tested cylinder has both external leakage from the plug chamber and internal leakage from the plug chamber to the rod chamber, the piston of the first leakage feedback cylinder will move to the right, and the piston of the second leakage feedback cylinder will also move to the right. In this case, the dial indicator readings will both increase. Furthermore, under these circumstances, ΔG1 > ΔG2 > 0.

[0054] Furthermore, the mechanical displacement measuring element is a dial indicator, and the determination method in step 8 is as follows:

[0055] 1) When there is external leakage in the cylinder rod chamber under test, the piston of the second leakage feedback cylinder will move to the left, and the reading of dial indicator G2 will decrease by ΔG2; the piston of the first leakage feedback cylinder will remain stationary, and the reading of dial indicator G1 will not change. Therefore, in this case, ΔG2>0, ΔG1=0;

[0056] 2) When there is internal leakage from the rod chamber to the plug chamber in the tested cylinder, the piston of the second leakage feedback cylinder will move to the left, and the piston of the first leakage feedback cylinder will also move to the left. At this time, the readings of dial indicators G2 and G1 will both decrease. Furthermore, in this case, ΔG2 = ΔG1 > 0.

[0057] 3) When the tested cylinder has both external leakage from the rod chamber and internal leakage from the rod chamber to the plug chamber, the piston of the second leakage feedback cylinder will move to the left, and the piston of the first leakage feedback cylinder will also move to the left. At this time, the readings of dial gauges G2 and G1 will both decrease; at this moment, ΔG2>ΔG1>0.

[0058] This invention enables leakage to be represented numerically, providing accurate feedback on the severity of the leakage. By digitizing the leakage data, it helps to manage the condition of the tested cylinder throughout its entire life cycle, making the maintenance process more efficient and less haphazard.

[0059] Furthermore, it can accurately report leaks that are not visible to the naked eye.

[0060] It can also automate the detection process, and does not require high skills from hydraulic system maintenance personnel.

[0061] Furthermore, this invention does not cause oil waste or environmental pollution when performing leak detection.

[0062] Implementers can assemble and construct equipment components according to existing conditions and budget. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the working principle of a hydraulic cylinder leakage detection device.

[0064] Figure 2 This is a sequence diagram of the leak detection process.

[0065] Figure 3 This is a diagram showing the hydraulic oil flow direction when the tested cylinder moves to the right.

[0066] Figure 4 This is a diagram showing the hydraulic oil flow direction during exhaust from the left and right chambers of the first leakage feedback cylinder.

[0067] Figure 5 This is a diagram showing the hydraulic oil flow direction during pressurized leakage detection in a plug chamber.

[0068] Figure 6 This is a diagram showing the hydraulic oil flow direction when the tested cylinder moves to the left.

[0069] Figure 7 This is a diagram showing the hydraulic oil flow direction during exhaust from the left and right chambers of the second leakage feedback cylinder.

[0070] Figure 8 This is a diagram showing the hydraulic oil flow direction during pressurized leakage detection in the rod chamber.

[0071] Figure 9 Working principle diagram of the hydraulic cylinder leakage detection device as an alternative solution;

[0072] Figure 10 The working principle diagram of the hydraulic cylinder leakage detection device for alternative solution two;

[0073] Figure 11 The working principle diagram of the hydraulic cylinder leakage detection device for alternative solution three;

[0074] Figure 12 The working principle diagram of the hydraulic cylinder leakage detection device for alternative solution four;

[0075] Figure 13 The working principle diagram of the hydraulic cylinder leakage detection device for alternative solution five;

[0076] Reference numerals: Cylinder under test 1, Plug chamber 15, Rod chamber 16, Directional control valve 2, Control valve left coil 21, Control valve right coil 22, First solenoid directional valve 3, First solenoid valve left coil 31, First solenoid valve right coil 32, Second solenoid directional valve 4, Second solenoid valve left coil 41, Second solenoid valve right coil 42, First solenoid switch valve 5, Second solenoid switch valve 6, First solenoid switch valve coil 51, Second solenoid switch valve coil 61, First throttle port 7, Second throttle port 8, First analog sensor 9, Second analog sensor 10, First leakage feedback cylinder 11, First leakage feedback cylinder left chamber 111, First leakage feedback cylinder right chamber 112, Second leakage feedback cylinder 12, Second leakage feedback cylinder left chamber 121, Second leakage feedback cylinder right chamber 122, Quick connector 13. Detailed Implementation

[0077] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. For ease of understanding, the following reference numerals are used; the terms "up," "down," "left," "right," "front," and "back" are used only for clarity. The dashed box represents the base portion. Example 1

[0078] Combination Figure 1 This embodiment discloses a technical solution for a hydraulic cylinder leakage detection device, which is described below:

[0079] A hydraulic cylinder leakage detection device, located between the hydraulic oil supply line and the tested cylinder 1, wherein a cylinder directional control valve is provided on the hydraulic oil supply line, characterized in that it includes:

[0080] The base serves as the component carrier for the hydraulic cylinder leakage detection module. The base contains hydraulic oil circuits, which are used to connect various control valves, cylinders, and external interfaces.

[0081] Connecting component, used to connect a hydraulic cylinder leakage detection device between the tested cylinder and the cylinder directional control valve;

[0082] A leakage feedback cylinder is used to detect piston displacement when a leak occurs, and the control system calculates and reflects the distance the piston moves.

[0083] The feedback module is used to measure the movement of the piston in the leakage feedback cylinder and send the movement to the control system.

[0084] The throttling module is used to perform venting of the leakage feedback cylinder;

[0085] The switch module is used to control the exhaust of the leakage feedback cylinder chamber;

[0086] The reversing module is used to control the action sequence of each valve and to detect the leakage status of the tested cylinder.

[0087] The control system is used for controlling various modules and transmitting and receiving signals.

[0088] The connector is a quick-connect plug 13. The reversing module and / or switching module are electric valves. The reversing module includes a first solenoid reversing valve 3 and a second solenoid reversing valve 4, which are stacked valves fixed to the base. Their electromagnets are connected to the control system, which provides power to control the electromagnets. Both the first solenoid reversing valve 3 and the second solenoid reversing valve 4 are three-position four-way reversing valves. The switching module used to control the exhaust of the leakage feedback cylinder chamber is a solenoid switching valve using a ball seat type.

[0089] The first electromagnetic switch valve 5 and the second electromagnetic switch valve 6 included in the switch module are cartridge valves. They are screwed into the base body by the threads on the valve body and fixed to the base body. Their electromagnets are connected to the control system, and the control system provides power to control the electromagnets.

[0090] The throttling module is a throttling port.

[0091] The throttling module includes a first throttling port 7 and a second throttling port 8. The two throttling ports are two internal hexagon set screws with a small hole of 1mm in diameter in the center. They are tightened inside the base to create a change in the orifice diameter between the internal hydraulic oil passages, thereby creating a throttling control effect on the hydraulic oil.

[0092] The feedback module is an analog sensor.

[0093] The feedback module includes a first analog sensor 9 and a second analog sensor 10, which are fixed to the base by a sensor bracket and fixing bolts, and connected to the control system to input analog signals to the control system.

[0094] The leakage feedback cylinder of the leakage detection module includes a first leakage feedback cylinder 11 and a second leakage feedback cylinder 12. The leakage feedback cylinder uses a base as its cylinder body and includes a piston. Each end of the piston has a chamber, and a chamber spring is provided in each chamber. An end cap is provided at the chamber opening. One end of the chamber spring abuts against the end cap, and the other end abuts against the piston. The piston of the leakage feedback cylinder is located inside the base. A sensing iron is provided on the piston. The sensing iron is adapted to an analog signal sensor. The piston drives the sensing iron to move, thereby changing the analog signal input value of the analog signal sensor. The analog signal sensor metal sensing block is installed in the middle position of the piston through a thread and can move with the piston, causing the value fed back to the control system by the analog signal sensor to change. Through the calculation of the control system, the control system can determine the position state of the piston. The left chamber spring and the right chamber spring at both ends of the piston are used to keep the piston in the middle position. Before leakage detection and during the detection preparation process, the oil pressure at both ends of the piston is zero or equal. The chamber springs on both sides can reset the piston to the middle position to initialize the analog signal sensor and ensure that the piston has a margin for left and right movement during the subsequent detection process.

[0095] The main hardware of the leak detection module is mounted on the base. In addition to serving as the mounting carrier for each piece of hardware, the base also serves as the cylinder body for the first leak feedback cylinder 11 and the second leak feedback cylinder 12. Furthermore, it has various channels inside to connect the hardware units. The process holes left on its surface for processing these channels are sealed with plugs to prevent oil leakage.

[0096] The leakage feedback cylinder consists of the following components: a left chamber spring for the piston, a left end cap, a right chamber spring, a right end cap, and a metal sensing block for the analog sensor. The metal sensing block is threaded onto the piston at its center, allowing it to move with the piston. When a leak occurs, the piston shifts, causing the position of the metal sensing block on the analog sensor to change. This changes the value fed back to the control system by the analog sensor. Through calculation by the control system, the piston's movement distance is accurately reflected, allowing for an assessment of the oil leak.

[0097] The springs at both ends of the piston in the leakage feedback cylinder are used to keep the piston in the middle position. Before leakage detection and during the detection preparation process, the oil pressure at both ends of the piston is zero or equal. The springs on both sides can reset the piston to the middle position so as to initialize the analog sensor and ensure that the piston has a margin for left and right movement during the subsequent detection process.

[0098] Both the piston and end cap use combined Glyd rings for sealing, which provides a good sealing effect, reduces the possibility of external leakage, and thus ensures the reliability of the leakage detection module itself.

[0099] The solenoid switch valve used to control the exhaust of the leakage feedback cylinder chamber uses a ball seat valve, which has a good sealing effect and can strictly prevent leakage when closed.

[0100] The throttle orifice has an external thread and can be installed in the channel inside the base body through the threaded connection. The center is a circular hole with a diameter of 1mm. When venting the leakage feedback cylinder chamber, the hydraulic oil flows through this circular hole and is throttled, thereby forming a hydraulic resistance effect, which maintains a pressure difference between the two ends of the throttle orifice and distinguishes the pressure zone from the pressureless zone.

[0101] The three-position four-way solenoid valve is the control element that controls the leakage detection module to perform detection.

[0102] The quick-connect connectors P, T, A, and B are interfaces for connecting the original hydraulic system's directional control valve and the cylinder under test. They use a quick-connect method, allowing for simple and quick connection to the system during testing. Furthermore, they are in a closed state when not connected, thus ensuring that hydraulic oil inside the module does not flow out and air does not flow in.

[0103] refer to Figure 1 The first solenoid directional valve 3 and the second solenoid directional valve 4 are three-position four-way P-type valves, and the directional control valve 2 is a three-position four-way O-type valve. The oil inlet of the hydraulic cylinder leakage detection device is connected to the P-path of the first solenoid directional valve 3. The A-port of the first solenoid directional valve 3 is connected to the oil inlet of the left chamber 111 of the first leakage feedback cylinder. The oil outlet of the left chamber 111 of the first leakage feedback cylinder is connected to the oil inlet of the first switching valve 5. The oil outlet of the first switching valve 5 is connected to the working oil port B of the first oil circuit via the first throttle port 7 and is connected to the rod chamber 16 of the tested cylinder 1. The B-port of the first solenoid directional valve 3 is connected to the oil inlet of the right chamber 112 of the first leakage feedback cylinder. The oil outlet of chamber 112 is connected to the working oil port A via the second oil circuit and is connected to the plug chamber 15 of the tested cylinder 1; the return oil port of the hydraulic cylinder leakage detection device is connected to the P circuit of the second solenoid directional valve 4, the A port of the second solenoid directional valve 4 is connected to the oil inlet of the left chamber 121 of the second leakage feedback cylinder, and the oil outlet of the left chamber 121 of the second leakage feedback cylinder is connected to the first oil circuit to the working oil port B; the B port of the second solenoid directional valve 4 is connected to the oil inlet of the right chamber 122 of the second leakage feedback cylinder; the oil outlet of the right chamber 112 of the second leakage feedback cylinder is connected to the oil inlet of the second switching valve 6, and the oil outlet of the second switching valve 6 is connected to the second oil circuit to the working oil port A via the second throttle port 8.

[0104] The working principle diagram of the "hydraulic cylinder leakage detection module" is as follows: Figure 1 As shown, the module is connected to the directional control valve and the tested cylinder interface via quick-connect connectors P, T, A, and B, respectively. The base serves as the component carrier for the hydraulic cylinder leakage detection module. All components of the module are installed inside the base and on its surface. The base contains hydraulic oil circuits that connect the control valves, cylinders, and external interfaces.

[0105] The two three-position four-way solenoid directional valves are stacked valves and are fixed to the base by four hexagonal socket bolts. Their electromagnets are connected to the control system through a four-pin interface. The control system provides DC 24V power to control the electromagnets.

[0106] The electromagnetic switch valve is a cartridge valve, which is screwed into the base through the thread on the valve body. Its electromagnet is connected to the control system through an M12*1 four-pin interface. The control system provides DC 24V power to control the electromagnet.

[0107] The throttling orifice consists of two internal hexagonal set screws with 1mm diameter holes in the center, which are tightened inside the base to create a change in orifice diameter between the internal hydraulic oil passages, thereby achieving a throttling control effect on the hydraulic oil.

[0108] The first analog sensor 9 and the second analog sensor 10 are fixed to the base by sensor brackets and fixing bolts, and are connected to the control system through an M12*1 5-pin interface to input analog signals to the control system.

[0109] The first leakage feedback cylinder 11 and the second leakage feedback cylinder 12 use a base as the cylinder body. The piston is installed inside the base, and an induction iron is fixedly installed in the middle of the piston. The induction iron works in conjunction with the first analog sensor 9 and the second analog sensor 10. The piston drives the induction iron to move, thereby changing the analog input values ​​of the first analog sensor 9 and the second analog sensor 10, so that the control system can accurately determine the position state of the piston.

[0110] The first solenoid directional valve 3 and the second solenoid directional valve 4 are three-position four-way P-type valves. The directional control valve is a valve that comes with the measured system. This hydraulic cylinder leakage detection device can be adapted to various types of directional control valves, such as three-position four-way O-type valves, three-position four-way H-type valves, two-position four-way valves, etc. Example 2

[0111] This implementation provides a detailed explanation of the detection method, combined with... Figure 2 Explanation:

[0112] Part One:

[0113] 1. Pressure build-up in the piston cavity of the tested hydraulic cylinder;

[0114] 2. Discharge the leaked air from the cylinder chamber;

[0115] 3. Make the first leakage feedback cylinder 11 the necessary channel for oil to enter the plug cavity of the tested cylinder, and make the second leakage feedback cylinder 12 the necessary channel for oil to exit the rod cavity 16 of the tested cylinder 1.

[0116] 4. Check for external leakage at the oil pipe, joint, and end cap on the piston side of the cylinder, and check for internal leakage of hydraulic oil in the piston chamber through the piston to the rod chamber;

[0117] Part Two

[0118] 5. Pressure build-up in the rod chamber of the tested hydraulic cylinder;

[0119] 6. Discharge the leaked air from the cylinder chamber;

[0120] 7. Make the second leakage feedback cylinder the necessary channel for oil inlet to the rod chamber of the cylinder under test, and make the first leakage feedback cylinder the necessary channel for oil outlet to the plug chamber of the cylinder under test.

[0121] 8. Check for external leaks at the oil pipe, joint, and end cap on the rod chamber side of the hydraulic cylinder, and check for internal leaks of hydraulic oil in the rod chamber that flow through the piston to the piston chamber.

[0122] The determination method for step 4 is as follows:

[0123] 1) When there is external leakage in the piston chamber of the tested cylinder, the piston of the first leakage feedback cylinder 11 will move to the right. At this time, the first analog sensor 9 will sense the movement of the piston and feed back the movement distance ΔS1 to the control system; the piston of the second leakage feedback cylinder 12 will remain stationary, and the value ΔS2 fed back by the second analog sensor 10 will not change. Therefore, in this case, ΔS1>0, ΔS2=0;

[0124] 2) When there is internal leakage from the piston chamber to the rod chamber in the tested cylinder, the piston of the first leakage feedback cylinder 11 will move to the right, and the piston of the second leakage feedback cylinder 12 will also move to the right. The first analog sensor 9 and the second analog sensor 10 will both detect the movement of the pistons of the leakage feedback cylinders and feed back the movement distance to the control system. At this time, ΔS1=ΔS2>0;

[0125] 3) When the tested cylinder has both external leakage from the plug chamber and internal leakage from the plug chamber to the rod chamber, the piston of the first leakage feedback cylinder 11 will move to the right, and the piston of the second leakage feedback cylinder 12 will also move to the right. At this time, both the first analog sensor 9 and the second analog sensor 10 will sense the movement of the pistons of the leakage feedback cylinders and feed back the movement distance to the control system. In this case, ΔS1>ΔS2>0.

[0126] The determination method for step 8 is as follows:

[0127] 1) When there is external leakage in the cylinder rod chamber under test, the piston of the second leakage feedback cylinder 12 will move to the left. At this time, the second analog sensor 10 will sense the movement of the piston and feed back the movement distance ΔS2 to the control system; the piston of the first leakage feedback cylinder 11 will remain stationary, and the value fed back by the first analog sensor 9 will not change ΔS1=0. At this moment, ΔS2>0, ΔS1=0.

[0128] 2) When there is internal leakage from the rod chamber to the plug chamber in the tested cylinder, the piston of the second leakage feedback cylinder 12 will move to the left, and the piston of the first leakage feedback cylinder 11 will also move to the left. At this time, both analog sensors will sense the movement of the piston of the leakage feedback cylinder and feed back the movement distance to the control system. At this moment, ΔS2=ΔS1>0.

[0129] 3) When the tested cylinder has both external leakage from the rod chamber and internal leakage from the rod chamber to the plug chamber, the piston of the second leakage feedback cylinder 12 will move to the left, and the piston of the first leakage feedback cylinder 11 will also move to the left. At this time, both the second analog sensor 10 and the first analog sensor 9 will sense the movement of the piston of the leakage feedback cylinder and feed back the movement distance to the control system. At this moment, ΔS2>ΔS1>0.

[0130] Leak detection process action sequence reference Figure 2 The testing process is divided into two parts: one is when the tested cylinder 1 moves to the right, and pressure is built up in its left chamber. At this time, it is possible to detect whether there is external leakage at the oil pipe, joint, and end cap on the left side of the cylinder, and whether there is internal leakage of hydraulic oil in the left chamber flowing to the right chamber through the piston; the other is when the tested cylinder moves to the left, and pressure is built up in its right chamber. At this time, it is possible to detect whether there is external leakage at the oil pipe, joint, and end cap on the right side of the cylinder, and whether there is internal leakage of hydraulic oil in the right chamber flowing to the left chamber through the piston.

[0131] Taking the testing process when the tested cylinder moves to the right as an example, it is shown below:

[0132] refer to Figure 3 The tested cylinder 1 moves to the right and enters its position, showing the direction of its hydraulic oil flow.

[0133] When the right coil 22 of the original hydraulic system directional control valve 2 is energized, the tested cylinder 1 moves to the right and waits for it to reach its position before the piston rod is fully extended or the clamping action is completed.

[0134] refer to Figure 4The left chamber 111 and right chamber 112 of the first leakage feedback cylinder 11 are vented, and the right coil 22 of the original hydraulic system directional control valve 2 remains energized. At this time, both the left chamber 111 and the right chamber 112 of the first leakage feedback cylinder are in the pressure zone. The function of the throttle ports 7 and 8 is to form hydraulic resistance when the hydraulic oil flows through them, separating the pressure zone from the pressureless zone and maintaining the pressure stability of the pressure zone. The coil 51 of the first solenoid valve 5 and the coil 61 of the second solenoid valve 6 are energized, thereby connecting the pressure zone and the pressureless zone. The pressurized oil will flow to the pressureless zone through the left chamber 111 and the right chamber 112 of the first leakage feedback cylinder, thereby venting the air in these two chambers to ensure that the subsequent measurement process will not result in inaccurate measurements due to residual air.

[0135] refer to Figure 5 The leakage condition of the tested cylinder under pressure in its left chamber is detected, and its hydraulic oil flow diagram is presented.

[0136] After the air in the left chamber 111 and right chamber 112 of the first leakage feedback cylinder is expelled, the measurement process can begin. At this time, the first solenoid valve 5 and the second solenoid valve 6 are returned to the closed state, and the right coil 22 of the original hydraulic system directional control valve 2 remains energized. The right coil 32 of the first three-position four-way solenoid directional valve 3 is energized, and the first leakage feedback cylinder 11 becomes the necessary path for hydraulic oil to enter the piston chamber 15 of the tested cylinder 1; the left coil 41 of the second three-position four-way solenoid directional valve 4 is energized, and the second leakage feedback cylinder 12 becomes the necessary path for hydraulic oil to flow out of the rod chamber 16 of the tested cylinder 1.

[0137] Based on the results, there are three possible scenarios:

[0138] Scenario 1: When there is an external leak in the piston chamber 15 of the tested cylinder 1, the piston of the first leakage feedback cylinder 11 will move to the right. At this time, the first analog sensor 9 will sense the piston's movement and feed back the movement distance ΔS1 to the control system; the piston of the second leakage feedback cylinder 12 will remain stationary, and the value ΔS2 fed back by the analog sensor S2 will not change. Therefore, in this case, ΔS1>0, ΔS2=0.

[0139] Scenario 2: When there is internal leakage from the piston chamber 15 to the rod chamber 16 in the tested cylinder 1, the piston of the first leakage feedback cylinder 11 will move to the right, and the piston of the second leakage feedback cylinder 12 will also move to the right. At this time, both the first analog sensor 9 and the second analog sensor 10 will sense the movement of the pistons in the leakage feedback cylinders and feed back the movement distance to the control system. In this case, ΔS1 = ΔS2 > 0

[0140] Scenario 3: When the tested cylinder 1 experiences both external leakage from the plug chamber 15 and internal leakage from the plug chamber 15 to the rod chamber 16, the piston of the first leakage feedback cylinder 11 will move to the right, and the piston of the second leakage feedback cylinder 12 will also move to the right. At this time, both the first analog sensor 9 and the second analog sensor 10 will detect the movement of the pistons in the leakage feedback cylinders and feed back the movement distance to the control system. Furthermore, in this case, ΔS1>ΔS2>0.

[0141] Taking the testing process of the tested cylinder 1 moving to the left as an example, it is shown below:

[0142] refer to Figure 6 The tested cylinder 1 moves to the left and reaches its position, showing its hydraulic oil flow direction diagram.

[0143] When the left coil 21 of the original hydraulic system directional control valve 2 is energized, the tested cylinder 1 moves to the left and waits for it to reach its position.

[0144] refer to Figure 7 The left chamber 121 of the second leakage feedback cylinder and the right chamber 122 of the second leakage feedback cylinder exhaust, presenting their hydraulic oil flow diagram.

[0145] The left coil 21 of the original hydraulic system directional control valve 2 remains energized. At this time, both the left chamber 121 and the right chamber 122 of the second leakage feedback cylinder are in the pressure zone. The function of the first throttle orifice 7 and the second throttle orifice 8 is to form hydraulic resistance when the hydraulic oil flows through them, separating the pressure zone from the pressureless zone and maintaining the pressure stability of the pressure zone. The coil 51 of the first solenoid valve 5 and the coil 61 of the second solenoid valve 6 are energized, thereby connecting the pressure zone and the pressureless zone. The pressurized oil will flow to the pressureless zone through the left chamber 121 and the right chamber 122 of the second leakage feedback cylinder, thereby venting the air in these two chambers to ensure that the subsequent measurement process will not result in inaccurate measurements due to residual air.

[0146] refer to Figure 8 The leakage condition of the tested cylinder 1 under pressure in its rod chamber 16 is detected, and its hydraulic oil flow diagram is presented.

[0147] After the air in the left chamber 121 and right chamber 122 of the second leakage feedback cylinder is expelled, the measurement process can begin. At this time, the first solenoid valve 5 and the second solenoid valve 6 are returned to the closed state, and the left coil 21 of the original hydraulic system directional control valve 2 remains energized. The left coil 41 of the second three-position four-way solenoid directional valve 4 is energized, and the second leakage feedback cylinder 12 becomes the necessary path for hydraulic oil to enter the rod chamber 16 of the tested cylinder 1; the right coil 32 of the first three-position four-way solenoid directional valve 3 is energized, and the first leakage feedback cylinder 11 becomes the necessary path for hydraulic oil to flow out of the plug chamber 15 of the tested cylinder 1.

[0148] Based on the results, there are three possible scenarios:

[0149] Scenario 1: When there is an external leak in the cylinder 1 rod chamber 16 under test, the piston of the second leakage feedback cylinder 12 will move to the left. At this time, the second analog sensor 10 will sense the piston's movement and feed back the movement distance ΔS2 to the control system; the piston of the first leakage feedback cylinder will remain stationary, and the value fed back by the first analog sensor 9 will not change. Therefore, in this case, ΔS2>0, ΔS1=0.

[0150] Scenario 2: When there is internal leakage from the rod chamber 16 to the plug chamber 15 in the tested cylinder 1, the piston of the second leakage feedback cylinder 12 will move to the left, and the piston of the first leakage feedback cylinder 11 will also move to the left. At this time, both the second analog sensor 10 and the first analog sensor 9 will sense the movement of the pistons in the leakage feedback cylinders and feed back the movement distance to the control system. Furthermore, in this case, ΔS2 = ΔS1 > 0.

[0151] Scenario 3: When the tested cylinder 1 has both external leakage from the rod chamber 16 and internal leakage from the rod chamber 16 to the plug chamber 15, the piston of the second leakage feedback cylinder 12 will move to the left, and the piston of the first leakage feedback cylinder 11 will also move to the left. At this time, both the second analog sensor 10 and the first analog sensor 9 will detect the movement of the pistons of the leakage feedback cylinders and feed back the movement distance to the control system. Furthermore, in this case, ΔS2 > ΔS1 > 0. Example 3

[0152] refer to Figure 9 In this embodiment, a manually controlled valve is used instead of a solenoid controlled valve. A three-position four-way solenoid directional valve can also be a manually controlled three-position four-way valve. The solenoid switch valve can also be a manually controlled shut-off valve, a manually controlled cartridge valve, or a stack valve.

[0153] This embodiment can also detect the leakage status of the tested cylinder by manually controlling the action sequence of each valve. Compared with the solution in embodiment 1, its advantages are lower manufacturing cost and no need for complex electrical control; its disadvantage is that it cannot achieve a fully automated detection process. Example 4

[0154] refer to Figure 12 The three-position four-way directional valve was replaced by a two-position four-way directional valve.

[0155] The electromagnetic switching valve can also be a manually operated shut-off valve, a manually controlled cartridge valve, or a stacked valve. The reversing module includes a first two-position four-way reversing valve and a second two-position four-way reversing valve. The first two-position four-way reversing valve is a p-type side-position valve with P-way A and T-way B; the second two-position four-way reversing valve is a p-type side-position valve with P-way B and T-way A. This embodiment uses two two-position four-way electromagnetic reversing valves instead of two three-position four-way electromagnetic reversing valves. This can be used as a backup solution if three-position four-way reversing valves are not available. However, the two two-position four-way valves have different functions, so two different valves need to be purchased or manufactured when making the leakage detection module. When using three-position four-way valves, the two valves are completely identical, reducing the cost of stocking or manufacturing.

[0156] Example 5

[0157] This embodiment uses a mechanical displacement measuring element instead of an analog sensor to detect the piston movement of the leakage feedback cylinder.

[0158] In this embodiment, the three-position four-way valve uses a p-type design. A dial indicator is used instead of an analog sensor to measure the movement of the piston in the leakage feedback cylinder. The probe of the dial indicator is connected to the contact rod on the piston of the leakage feedback cylinder. When the piston moves, the contact rod will simultaneously drive the probe of the dial indicator to move. The reading of the dial indicator needle will reflect the movement distance of the piston, thus allowing for accurate determination of the piston's position change and movement distance.

[0159] The method for judging the measurement results is as follows (assuming that dial indicators G1 and G2 are both located on the right side of their respective leakage feedback cylinders, then when the piston of the leakage feedback cylinder moves to the right, the dial indicator reading increases; when the piston of the leakage feedback cylinder moves to the left, the dial indicator reading decreases):

[0160] When the tested cylinder moves to the right, the following three situations are considered for judgment:

[0161] In scenario one, if there is an external leak in the plug chamber 15, the piston of the first leak feedback cylinder 11 will move to the right, and the reading of dial indicator G1 will increase by ΔG1. The piston of the second leak feedback cylinder will remain stationary, and the reading of dial indicator G2 will not change. Therefore, in this case, ΔG1 > 0, and ΔG2 = 0.

[0162] Scenario 2: When there is internal leakage from the piston chamber 15 to the rod chamber 16 in the tested cylinder 1, the piston of the first leakage feedback cylinder 11 will move to the right, and the piston of the second leakage feedback cylinder 12 will also move to the right. At this time, the readings of dial indicators G1 and G2 will both increase. In this case, ΔG1 = ΔG2 > 0.

[0163] Scenario 3: When the tested cylinder 1 has both external leakage from the plug chamber 15 and internal leakage from the plug chamber 15 to the rod chamber 16, the piston of the first leakage feedback cylinder 11 will move to the right, and the piston of the second leakage feedback cylinder 12 will also move to the right. In this case, the readings of dial indicators G1 and G2 will both increase. Furthermore, in this situation, ΔG1 > ΔG2 > 0.

[0164] When the tested hydraulic cylinder 1 moves to the left, the following three situations are considered for judgment:

[0165] In scenario one, when there is an external leak in the rod chamber 16, the piston of the second leakage feedback cylinder 12 will move to the left, and the reading of dial indicator G2 will decrease by ΔG2; the piston of the first leakage feedback cylinder will remain stationary, and the reading of dial indicator G1 will not change. Therefore, in this case, ΔG2>0, ΔG1=0.

[0166] In scenario two, when there is internal leakage from the rod chamber 16 to the plug chamber 15 in the tested cylinder 1, the piston of the second leakage feedback cylinder 12 will move to the left, and the piston of the first leakage feedback cylinder 11 will also move to the left. At this time, the readings of dial indicators G2 and G1 will both decrease. In this case, ΔG2 = ΔG1 > 0.

[0167] Scenario 3: When the tested cylinder 1 has both external leakage from the rod chamber 16 and internal leakage from the rod chamber 16 to the plug chamber 15, the piston of the second leakage feedback cylinder 12 will move to the left, and the piston of the first leakage feedback cylinder 11 will also move to the left. At this time, the readings of dial indicators G2 and G1 will both decrease. In this case, ΔG2 > ΔG1 > 0. Example 6

[0168] refer to Figure 10 This embodiment combines the manual control valve and dial indicator from Alternative Solution 1 with Embodiments 3 and 5, enabling a fully mechanical "hydraulic cylinder leakage detection module" without any electrical control. Its advantage is that it can further reduce manufacturing costs; its disadvantage is that it cannot achieve an automated detection process, requires highly skilled operators, and the measurement process takes a long time. Example 7

[0169] refer to Figure 13In this embodiment, a pipe connector and hydraulic hose are used to connect the leakage detection module between the tested cylinder and the cylinder directional control valve, instead of using the quick-connect connector 13. This embodiment uses a hydraulic hose and pipe connector to connect the hydraulic cylinder leakage detection module between the tested cylinder and the cylinder directional control valve. Its advantage over the quick-connect connector 13 connection method in Embodiment 1 is reduced manufacturing cost. However, the connection process is not as quick. Example 8

[0170] refer to Figure 11 As a preferred embodiment, this embodiment uses an adjustable throttle valve instead of the non-adjustable flow port in embodiment 1. Its advantage is that the throttling effect of the throttle valve can be manually adjusted, so that the hydraulic cylinder leakage detection module can achieve the best effect when performing the venting process of the leakage feedback cylinder.

[0171] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydraulic cylinder leakage detection device, located between a hydraulic oil supply circuit and the cylinder under test, wherein a cylinder directional control valve is provided on the hydraulic oil supply circuit, characterized in that... ,include: The base serves as a component carrier for a hydraulic cylinder leakage detection device, and the base contains hydraulic oil passages. The connector is used to connect the hydraulic cylinder leakage detection device between the tested cylinder and the cylinder directional control valve. A leakage feedback cylinder is used to detect piston displacement when a leak occurs, and the control system calculates the piston's movement distance. The leakage feedback cylinder includes a first leakage feedback cylinder and a second leakage feedback cylinder. The base body serves as the cylinder body. Each leakage feedback cylinder includes a piston with a chamber at each end. A chamber spring is located within each chamber, and an end cap is located at the chamber opening. One end of the chamber spring abuts against the end cap, and the other end abuts against the piston. The left and right chamber springs at both ends of the piston are used to maintain the piston in a neutral position. The feedback module measures the movement of the piston in the leakage feedback cylinder and sends this movement to the control system. The feedback module is a mechanical displacement measuring element or an analog sensor. The analog sensor includes a first analog sensor and a second analog sensor, which are fixed to the base by a sensor bracket and fixing bolts, connected to the control system, and input analog signals to the control system. The piston is equipped with a sensing iron, which is adapted to the analog sensor. The piston drives the sensing iron to move, thereby changing the analog input value of the analog sensor. A throttling module is used to vent the leakage feedback cylinder; the throttling module includes a first throttling port and a second throttling port, the two throttling ports being two internal hexagon set screws with central openings, which are tightened inside the base body to create a change in orifice diameter between the internal hydraulic oil passages, thereby controlling the flow of hydraulic oil. A switching module is used to control the exhaust of the leakage feedback cylinder chamber; the switching module includes a first electromagnetic switching valve and a second electromagnetic switching valve, which are cartridge valves that are screwed into the base body by the threads on the valve body and fixed to the base body. Their electromagnets are connected to the control system, and the control system provides power to control the electromagnets. The reversing module is used to control the action sequence of each valve and to detect the leakage status of the tested cylinder. The reversing module includes a first electromagnetic reversing valve and a second electromagnetic reversing valve, which are in the form of superimposed valves and fixed to the base. Their electromagnets are connected to the control system, and the control system provides power to control the electromagnets. Both the first electromagnetic reversing valve and the second electromagnetic reversing valve are three-position four-way reversing valves. The control system is used for controlling various modules and transmitting and receiving signals. The first and second electromagnetic directional valves are three-position four-way P-type valves. The inlet of the hydraulic cylinder leakage detection device is connected to the P-path of the first electromagnetic directional valve. Port A of the first electromagnetic directional valve is connected to the inlet of the left chamber of the first leakage feedback cylinder. The outlet of the left chamber of the first leakage feedback cylinder is connected to the inlet of the first electromagnetic switch valve. The outlet of the first electromagnetic switch valve is connected to the working port B of the first oil circuit via the first throttle port and is connected to the rod chamber of the cylinder under test. Port B of the first electromagnetic directional valve is connected to the inlet of the right chamber of the first leakage feedback cylinder. The outlet of the right chamber of the first leakage feedback cylinder is connected to the second... The oil circuit to the working port A is connected to the plug cavity of the tested oil cylinder; the return port of the hydraulic cylinder leakage detection device is connected to the second electromagnetic directional valve P circuit, the second electromagnetic directional valve A port is connected to the oil inlet of the left chamber of the second leakage feedback cylinder, and the oil outlet of the left chamber of the second leakage feedback cylinder is connected to the first oil circuit to the working port B; the second electromagnetic directional valve B port is connected to the oil inlet of the right chamber of the second leakage feedback cylinder; the oil outlet of the right chamber of the second leakage feedback cylinder is connected to the oil inlet of the second electromagnetic switch valve, and the oil outlet of the second electromagnetic switch valve is connected to the second oil circuit to the working port A via the second throttle port.

2. The hydraulic cylinder leakage detection device according to claim 1, characterized in that, The connection element is a quick-connect plug or a hydraulic hose.

3. The hydraulic cylinder leakage detection device according to claim 1, characterized in that, The switching module used to control the exhaust of the leakage feedback cylinder chamber is an electromagnetic switch valve, which is a ball seat valve.

4. The hydraulic cylinder leakage detection device according to claim 1, characterized in that, The analog sensor metal sensing block is threadedly installed at the middle position of the piston and can move with the piston, causing the value fed back to the control system by the analog sensor to change. Through the calculation of the control system, the control system can determine the position state of the piston. Before and during leak detection, the oil pressure at both ends of the piston is zero or equal. The chamber springs on both sides can reset the piston to the middle position to initialize the analog sensor and ensure that the piston has room to move left and right during the subsequent detection process.

5. A hydraulic cylinder leakage detection device according to claim 1, characterized in that, Both the piston and the end cap use combined Glyd ring seals.

6. A method for detecting leakage in a hydraulic cylinder, comprising the hydraulic cylinder leakage detection device as described in any one of claims 1-5, characterized in that, The steps are as follows: Part One: 1) The pressure built up in the piston cavity of the tested hydraulic cylinder; 2) Expel the air from the leak feedback cylinder chamber; 3) Make the first leakage feedback cylinder the necessary channel for oil to enter the plug chamber of the cylinder under test, and make the second leakage feedback cylinder the necessary channel for oil to exit the rod chamber of the cylinder under test. 4) Check for external leaks at the oil pipe, joint, and end cap on the piston side of the cylinder, and for internal leaks of the hydraulic oil in the piston chamber flowing from the piston to the rod chamber. Part Two 5) Pressure build-up in the rod chamber of the tested cylinder; 6) Release the air from the leak feedback cylinder chamber; 7) Make the second leakage feedback cylinder the necessary channel for oil inlet to the rod chamber of the cylinder under test, and make the first leakage feedback cylinder the necessary channel for oil outlet to the plug chamber of the cylinder under test. 8) Check for external leaks at the oil pipe, joint, and end cap on the rod chamber side of the hydraulic cylinder, and check for internal leaks of hydraulic oil in the rod chamber that flow through the piston to the piston chamber.

7. A method for detecting leakage in a hydraulic cylinder according to claim 6, characterized in that, The determination method for step 4 is as follows: 1) When there is an external leak in the cylinder chamber under test, the piston of the first leakage feedback cylinder will move to the right. At this time, the first analog sensor will sense the movement of the piston and feed back the movement distance ΔS1 to the control system; the piston of the second leakage feedback cylinder will remain stationary, and the value ΔS2 fed back by the second analog sensor will not change. Therefore, in this case, ΔS1>0, ΔS2=0. 2) When there is internal leakage from the plug chamber to the rod chamber in the tested cylinder, the piston of the first leakage feedback cylinder will move to the right, and the piston of the second leakage feedback cylinder will also move to the right. Both the first analog sensor and the second analog sensor will sense the movement of the piston of the leakage feedback cylinder and feed back the movement distance to the control system. At this time, ΔS1=ΔS2>0. 3) When the tested cylinder has both external leakage from the plug chamber and internal leakage from the plug chamber to the rod chamber, the piston of the first leakage feedback cylinder will move to the right, and the piston of the second leakage feedback cylinder will also move to the right. At this time, both the first analog sensor and the second analog sensor will sense the movement of the piston of the leakage feedback cylinder and feed back the movement distance to the control system. At this time, ΔS1>ΔS2>0.

8. A method for detecting leakage in a hydraulic cylinder according to claim 6, characterized in that, The determination method for step 8 is as follows: 1) When there is an external leakage in the cylinder rod chamber under test, the piston of the second leakage feedback cylinder will move to the left. At this time, the second analog sensor will sense the movement of the piston and feed back the movement distance ΔS2 to the control system; the piston of the first leakage feedback cylinder will remain stationary, and the value fed back by the first analog sensor will not change ΔS1=0. At this moment, ΔS2>0, ΔS1=0. 2) When there is internal leakage from the rod chamber to the plug chamber in the tested cylinder, the piston of the second leakage feedback cylinder will move to the left, and the piston of the first leakage feedback cylinder will also move to the left. At this time, both analog sensors will sense the movement of the piston of the leakage feedback cylinder and feed back the movement distance to the control system. At this moment, ΔS2=ΔS1>0. 3) When the tested cylinder has both external leakage from the rod chamber and internal leakage from the rod chamber to the plug chamber, the piston of the second leakage feedback cylinder will move to the left, and the piston of the first leakage feedback cylinder will also move to the left. At this time, both the second analog sensor and the first analog sensor will sense the movement of the piston of the leakage feedback cylinder and feed back the movement distance to the control system. At this moment, ΔS2>ΔS1>0.

9. A method for detecting leakage in a hydraulic cylinder according to claim 6, characterized in that, The mechanical displacement measuring element is a dial indicator, and the determination method in step 4 is as follows: 1) When there is external leakage in the cylinder chamber under test, the piston of the first leakage feedback cylinder will move to the right, and the reading of dial gauge G1 will increase by ΔG1; the piston of the second leakage feedback cylinder will remain stationary, and the reading of dial gauge G2 will not change. Therefore, in this case, ΔG1>0 and ΔG2=0. 2) When there is internal leakage from the plug chamber to the rod chamber in the tested cylinder, the piston of the first leakage feedback cylinder will move to the right, and the piston of the second leakage feedback cylinder will also move to the right. At this time, the readings of dial gauges G1 and G2 will increase, and under this condition, ΔG1=ΔG2>0. 3) When the tested cylinder has both external leakage from the plug chamber and internal leakage from the plug chamber to the rod chamber, the piston of the first leakage feedback cylinder will move to the right, and the piston of the second leakage feedback cylinder will also move to the right. At this time, the dial gauge reading will increase, and under this condition, ΔG1>ΔG2>0.

10. A method for detecting leakage in a hydraulic cylinder according to claim 6, characterized in that, The mechanical displacement measuring element is a dial indicator, and the determination method in step 8 is as follows: 1) When there is external leakage in the cylinder rod chamber under test, the piston of the second leakage feedback cylinder will move to the left, and the reading of dial gauge G2 will decrease by ΔG2; the piston of the first leakage feedback cylinder will remain stationary, and the reading of dial gauge G1 will not change. Therefore, in this case, ΔG2>0, ΔG1=0. 2) When there is internal leakage from the rod chamber to the plug chamber in the tested cylinder, the piston of the second leakage feedback cylinder will move to the left, and the piston of the first leakage feedback cylinder will also move to the left. At this time, the readings of dial gauges G2 and G1 will decrease, and under this condition, ΔG2=ΔG1>0. 3) When the tested cylinder has both external leakage from the rod chamber and internal leakage from the rod chamber to the plug chamber, the piston of the second leakage feedback cylinder will move to the left, and the piston of the first leakage feedback cylinder will also move to the left. At this time, the readings of dial gauges G2 and G1 will both decrease; at this moment, ΔG2>ΔG1>0.

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