Test device and test method for simulating eccentric load working condition of sealing ring

Abstract

The application provides a test device and test method for simulating eccentric partial load working conditions of sealing rings, and belongs to the technical field of hydraulic sealing performance testing. The device comprises a signal acquisition and control unit, a linear driving unit, a hinged unit, a test cylinder unit, a test shaft unit, a lateral loading unit and a hydraulic system unit. The linear driving unit is connected with a circular grating. The hinged unit comprises a first pin shaft, a second pin shaft, a first connecting rod and a second connecting rod. The test shaft unit comprises a first tension and pressure sensor, a first test shaft, a second tension and pressure sensor and a second test shaft connected in sequence. The test cylinder unit comprises a cylinder body and end covers arranged on both axial sides of the cylinder body. The lateral loading unit comprises two groups of loading mechanisms. The application can accurately construct and stably maintain eccentric partial load working conditions, can realize decoupling measurement of the friction force of multiple sealing rings, can support synchronous acquisition of multiple parameters and has strong engineering applicability, and has good engineering popularization value.

Description

Technical Field

[0001] This invention relates to the field of hydraulic sealing performance testing technology, specifically to a test device and test method for simulating eccentric and eccentric load conditions of a sealing ring. Background Technology

[0002] Hydraulic seals are widely used in hydraulic cylinders, hydraulic valves, and other actuators. Their sealing performance directly affects the efficiency, reliability, and service life of the hydraulic system unit. In practical engineering applications, due to factors such as assembly errors, structural deformation, and external loads, the piston rod or piston of a hydraulic cylinder is often in a certain degree of eccentricity or off-center loading. This causes the seals to work under non-coaxial conditions, resulting in increased local contact stress, changes in friction, and increased leakage, thereby accelerating seal failure.

[0003] To accurately evaluate the performance of the sealing ring under the aforementioned complex working conditions, simulation tests using specialized testing equipment are required. However, existing technologies still have the following significant shortcomings: Limited ability to construct eccentric and off-center load conditions: Most existing hydraulic seal test benches can only achieve ideal coaxial loading and cannot actively introduce controllable eccentricity or off-center load angle; the few devices with lateral loading function mostly adopt fixed push-press structure, and the loading parameters are difficult to adjust and quantify accurately, and the repeatability is poor, making it difficult to truly reproduce the off-center load state in actual service.

[0004] Insufficient accuracy in measuring the friction force of sealing rings: Existing devices typically fail to effectively distinguish between the friction force of the sealing ring itself and the inherent friction interference generated by the test system when testing friction force; especially after applying lateral load, the additional friction component increases significantly, resulting in a distortion of the measured total friction force, which cannot accurately reflect the true friction characteristics of the sealing ring.

[0005] Multi-parameter synchronous acquisition: Existing test systems generally lack the ability to acquire key parameters such as friction, leakage, system pressure, temperature and movement speed synchronously.

[0006] The stability of the test conditions and its applicability to engineering are poor: some devices are difficult to maintain the set eccentric or off-center loading state during reciprocating motion, and the loading mechanism is prone to attitude drift due to motion inertia or vibration interference, resulting in large dispersion of test data; in addition, the structural design is complex and the adjustment method is not intuitive, which is not conducive to quickly changing test pieces or adapting to the test requirements of different specifications of sealing rings.

[0007] Therefore, there is an urgent need to develop a new type of sealing ring performance testing device that can quantitatively construct and stably maintain eccentric loading conditions, accurately separate the friction force of the sealing ring, support simultaneous acquisition of multiple parameters and decoupling testing of multiple seals, and has a clear structure and convenient adjustment. Summary of the Invention

[0008] To address the shortcomings of the prior art, the present invention aims to provide a test apparatus and method for simulating the eccentric and off-center load conditions of a sealing ring, thereby solving the problem that existing test equipment cannot accurately reproduce the eccentric and off-center load conditions experienced by the sealing ring in actual operation.

[0009] Specifically, on the one hand, the present invention provides a test device for simulating the eccentric and eccentric loading condition of a sealing ring, which includes a linear drive unit, a hinge unit, a test shaft unit, a test cylinder unit, a lateral loading unit, and a hydraulic system unit; The linear drive unit includes a circular grating for detecting the amount of displacement caused by the linear drive unit driving the hinge unit; The articulated unit includes a first link, a second link, a first pin, and a second pin. The first end of the first link is rotatably connected to the connecting sleeve of the linear drive unit through the first pin, and the second end of the first link is rotatably connected to the first end of the second link through the second pin. The test shaft unit includes a first tension / compression sensor, a first test shaft, a second tension / compression sensor, and a second test shaft connected in sequence. The first tension / compression sensor is connected to the second end of the second connecting rod of the hinge unit. The first tension / compression sensor is used to measure the tension applied to the first test shaft by the linear drive unit. The second tension / compression sensor is used to measure the tension applied to the second test shaft by the first test shaft. The test cylinder unit includes a cylinder body and end caps located on both sides of the cylinder body along its axial direction; the top of the cylinder body is provided with an oil inlet for connection with the hydraulic system unit; the end caps are provided with end cap holes for the test shaft unit to pass through; and a sealing groove is provided on the inner circumferential surface of the end cap holes for installing the sealing ring to be tested. The lateral loading unit includes loading mechanisms symmetrically arranged on both sides of the outside of the test cylinder; each loading mechanism includes a guide rail, a slider, a hydraulic lifting mechanism, and a support; the lower end of the slider is slidably connected to the guide rail, and the upper end of the slider is in contact with the outer surface of the test shaft unit; the support and the hydraulic lifting mechanism are both located at the bottom of the guide rail and are rotatably connected to the guide rail.

[0010] Preferably, the end cap is provided with a drainage hole. The opening of the first end of the drainage hole is located on the side of the sealing groove away from the inside of the cylinder body, and the opening of the second end of the drainage hole is connected to the outside of the cylinder body. The drainage hole can guide the oil seeping out of the leakage gap between the sealing ring to be tested and the test shaft unit to the outside of the cylinder body.

[0011] Preferably, a pressure sensor is installed at the oil inlet, and a temperature sensor is installed inside the test cylinder unit.

[0012] Preferably, the first connecting rod is provided with a first hinged locking hole corresponding to the position of the first pin, and the second connecting rod is provided with a second hinged locking hole corresponding to the position of the second pin; the first pin and the second pin can be tightened by the first hinged locking hole and the second hinged locking hole to limit the relative rotation between the linear drive unit and the first connecting rod, and between the first connecting rod and the second connecting rod.

[0013] Preferably, the upper end of the slider is provided with a crescent-shaped rolling groove, which is in contact with the outer surface of the test shaft unit.

[0014] Preferably, the lower end of the slider is provided with a slider fixing mechanism for fixing the slider to the guide rail, and the slider fixing mechanism is located on both sides of the contact area between the slider and the guide rail.

[0015] Preferably, the linear drive unit includes a servo motor, a lead screw, a lead screw slide, a circular grating, and a connecting sleeve. The output end of the servo motor is fixedly connected to the lead screw, the lead screw is threadedly connected to the lead screw slide, the connecting sleeve is sleeved on the outside of the lead screw, and the lead screw slide is fixedly connected to the first end of the connecting sleeve. The second end of the connecting sleeve is rotatably connected to the first connecting rod through a first pin. The circular grating is sleeved on the outside of the lead screw.

[0016] On the other hand, the present invention provides a test method for a test device simulating eccentric and eccentric loading conditions of a sealing ring, which includes the following steps: S1. Adjust the hinge unit and the lateral loading unit according to the target eccentricity or target off-center loading angle, adjust the test shaft unit to the corresponding offset position, and lock the hinge unit and the lateral loading unit. S2. Calibrate the inherent friction force. Without installing the sealing ring, start the linear drive unit to make the test shaft unit reciprocate axially under the set eccentricity or off-center loading angle. Use the first tension / compression sensor and the second tension / compression sensor to collect and record the axial force signal of the system at this time as the reference data for subsequent friction force decoupling. S3. Install the sealing ring to be tested, inject hydraulic oil and adjust the pressure to the set value; after the pressure and temperature parameters stabilize, start the linear drive unit to drive the test shaft unit to make axial reciprocating motion along the preset eccentric or off-center load direction, and synchronously acquire multi-source signals through the servo motor, the first tension and compression sensor, the second tension and compression sensor, the pressure sensor, the temperature sensor and the drainage hole. S4. When the test reaches the preset termination condition, stop the test; based on the collected data throughout the process, calculate the key sealing performance indicators of the sealing ring under the eccentric or off-center load condition.

[0017] Preferably, the adjustment steps for the eccentric working condition are as follows: Based on the test objectives, the required target eccentricity is determined. The extension of the hydraulic jacking mechanism on both sides of the loading mechanism is simultaneously adjusted to cause the test shaft unit to translate as a whole, resulting in a radial offset of the test shaft unit's axis relative to the linear drive unit's axis. Subsequently, the radial offset is precisely corrected by finely adjusting the position of the slider on the guide rail, ensuring that the test shaft unit remains parallel to the test cylinder unit's axis. Throughout the adjustment process, the hinge unit moves accordingly, ensuring that the linear drive unit and the test shaft unit's axes remain parallel. The actual radial offset of the test shaft unit is measured in real time. When the error between the actual radial offset and the target eccentricity is within the allowable range, the slider and hinge unit positions are locked, completing the eccentricity setting.

[0018] Preferably, the adjustment steps for the off-center load condition are as follows: Determine the required target off-center load angle based on the test objectives, and adjust the extension of the hydraulic jacking mechanism on both sides of the loading mechanism. When the extensions of the two mechanisms are inconsistent, the test shaft unit is driven to tilt in the center, forming the actual off-center load angle. Subsequently, the actual off-center load angle is finely corrected by adjusting the position of the slider on the guide rail. During the entire adjustment process, the hinge unit moves accordingly to ensure that the linear drive unit and the test shaft unit maintain coordinated movement. The actual off-center load angle of the test shaft unit is measured in real time. When the error between the actual off-center load angle and the target off-center load angle is within the allowable range, the slider and the hinge unit are locked to complete the setting of the off-center load condition.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. It can accurately construct and stably maintain eccentric and off-center loading conditions: By symmetrically setting lateral loading units consisting of guide rails, sliders, supports and hydraulic jacking mechanisms on both sides of the test cylinder unit, the tilt angle of the guide rails can be adjusted by the hydraulic jacking mechanism, and the eccentricity and off-center loading angle can be quantitatively controlled to achieve high-fidelity simulation of actual service conditions; the loading state remains stable in reciprocating motion, with good repeatability and strong calibrability.

[0020] 2. Achieve decoupled measurement of friction force of multiple sealing rings: The first tension-compression sensor and the second tension-compression sensor are integrated in the test shaft unit. Combined with the inherent friction force calibration process (no-load operation test without sealing rings), the system friction interference introduced by the guide structure and support components can be effectively deducted, the friction force signal of the sealing ring itself can be accurately extracted, and the reliability of the test results can be significantly improved.

[0021] 3. Supports simultaneous acquisition of multiple parameters: The system integrates a data acquisition module to simultaneously acquire multi-dimensional parameters such as friction force, leakage, hydraulic pressure, oil temperature and axial movement speed, comprehensively characterizing the dynamic working characteristics of the sealing ring under eccentric or off-center load conditions.

[0022] 4. Strong engineering applicability: The overall layout of this invention is clear, the lateral loading unit adopts a modular design, and the height and angle adjustment is realized through the hydraulic lifting mechanism, which is easy to operate; the hinge unit allows for flexible adjustment of the test shaft installation position under the premise that the height of the linear drive unit is fixed, adapting to sealing ring specimens of different sizes, facilitating quick assembly and disassembly and batch testing, and has good engineering promotion value. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the test device for simulating the eccentric loading condition of the sealing ring according to the present invention. Figure 2 This is a schematic diagram of the structure of the test cylinder unit, test shaft unit, and lateral loading unit of the present invention; Figure 3 This is a schematic diagram illustrating the eccentric working condition principle of the present invention; Figure 4 This is a schematic diagram of the principle of the off-center load condition of the present invention.

[0024] Key reference numerals: 1. Connecting sleeve; 2. First connecting rod; 3. Second connecting rod; 4. Cylinder body; 5. Second test shaft; 6. Hydraulic system unit; 7. Lateral loading unit; 8. Drainage hole; 9. Temperature sensor; 10. Signal acquisition and control unit; 11. Hinge second settling hole; 12. First connecting mechanism; 13. First test shaft; 14. Second connecting mechanism; 15. Protective sleeve; 16. Second tension / compression sensor; 17. Sealing groove; 18. End cap; 19. Slider; 21. Support; 22. Guide rail; 23. Crescent-shaped rolling groove; 24. Hydraulic jacking mechanism; 25. Servo motor; 26. Circular grating; 27. Lead screw slide; 28. Hinge first settling hole. Detailed Implementation

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0026] like Figure 1 and Figure 2 As shown, the present invention provides a test device for simulating the eccentric loading condition of a sealing ring, which includes a linear drive unit, a hinge unit, a test shaft unit, a test cylinder unit, a lateral loading unit 7, and a hydraulic system unit 6.

[0027] The linear drive unit includes a servo motor 25, a lead screw, a lead screw slide 27, a circular grating 26, and a connecting sleeve 1. The output end of the servo motor 25 is fixedly connected to the lead screw, and the lead screw is threadedly connected to the lead screw slide 27. The connecting sleeve 1 is sleeved on the outside of the lead screw, and the lead screw slide 27 is fixedly connected to the first end of the connecting sleeve 1, so that the linear drive unit can drive the connecting sleeve 1 to move laterally. The second end of the connecting sleeve 1 is rotatably connected to the first end of the first connecting rod 2 through a first pin. The circular grating 26 is sleeved on the outside of the lead screw and connected to the linear drive unit, and is used to detect the displacement of the hinge unit driven by the linear drive unit in real time.

[0028] The articulated unit includes a first connecting rod 2, a second connecting rod 3, a first pin, and a second pin. The first end of the first connecting rod 2 is rotatably connected to the connecting sleeve of the linear drive unit via the first pin, and the second end of the first connecting rod 2 is rotatably connected to the first end of the second connecting rod 3 via the second pin. The second end of the second connecting rod 3 is connected to the test shaft unit. The first connecting rod 2 is provided with a first locking hole 28 corresponding to the position of the first pin, and the second connecting rod 3 is provided with a second locking hole 11 corresponding to the position of the second pin. After the adjustment of the articulated unit is completed, the first pin and the second pin can be tightened through the first locking hole 28 and the second locking hole 11 to limit the relative rotation between the linear drive unit and the first connecting rod 2, and between the first connecting rod 2 and the second connecting rod 3. This allows the linear drive unit, the articulated unit, and the test shaft unit to form a stable equivalent rigid connection, thereby ensuring the stable transmission of axial load and reducing the influence of vibration on the measurement results. Specifically, by adjusting the hinge unit, the test shaft assembly can undergo controllable radial offset or angular deflection relative to the linear drive mechanism while keeping the installation height of the linear drive unit constant, thereby accurately simulating the eccentricity and off-center load state of the seal ring under actual working conditions.

[0029] The test shaft unit includes a first tension / compression sensor, a first test shaft 13, a second tension / compression sensor 16, and a second test shaft 5 connected in sequence. The first tension / compression sensor is connected to the second end of the second connecting rod of the hinge unit. The first tension / compression sensor is used to measure the tension applied to the first test shaft 13 by the linear drive unit. The first tension / compression sensor is also used to measure the tension applied to the second test shaft 5 by the first test shaft 13. Specifically, the first tension / compression sensor is connected to the first test shaft 13 via a first connecting mechanism 12, and the first test shaft 13 is connected to the second tension / compression sensor 16 via a second connecting mechanism 14. A protective sleeve 15 is provided on the outside of the second tension / compression sensor 16 to isolate high-pressure oil and prevent oil contamination of the second tension / compression sensor 16. In a preferred embodiment, the outer diameters of the protective sleeve 15, the first test shaft 13, and the second test shaft 5 are substantially the same. In a preferred embodiment, the first test shaft 13 is a hollow shaft structure, allowing the second tension / compression sensor 16 to be connected to the outside of the test shaft unit via a wire.

[0030] The test cylinder unit includes a cylinder body 4 and end caps 18 located on both axial sides of the cylinder body 4. The top of the cylinder body 4 has an oil inlet for connection to a hydraulic system unit 6. The end caps 18 have end cap holes for the test shaft unit to pass through. A sealing groove 17 for installing the seal ring to be tested is formed on the inner circumferential surface of the end cap holes. The end caps 18 have drainage holes 8. The first end of the drainage hole 8 is located on the side of the sealing groove 17 away from the inside of the cylinder body 4, and the second end of the drainage hole connects to the outside of the cylinder body 4, guiding the oil seeping from the leakage gap between the seal ring to be tested and the test shaft unit to the outside of the cylinder body 4, thus forming a measurable leakage signal to provide a basis for sealing performance evaluation. A pressure sensor is also installed at the oil inlet, and a temperature sensor 9 is installed inside the test cylinder unit to monitor the pressure and temperature of the oil inside the test cylinder unit in real time during the test.

[0031] The lateral loading unit 7 includes loading mechanisms symmetrically arranged on both sides of the test cylinder 4. Each loading mechanism includes a guide rail 22, a slider 19, a hydraulic jacking mechanism 24, and a support 21. The lower end of the slider 19 is slidably connected to the guide rail 22, and the upper end of the slider 19 is in rolling contact with the outer surface of the test shaft unit. The bottom of the guide rail 22 is provided with a support 21 and a hydraulic jacking mechanism 24, both of which are rotatably connected to the guide rail 22. By adjusting the hydraulic jacking mechanism 24, the radial off-center load applied to the test shaft unit can be controlled, thereby simulating the actual stress state of the sealing ring under eccentric or off-center load conditions. Specifically, the upper end of the slider 19 is provided with a crescent-shaped rolling groove 23, which is in rolling contact with the outer surface of the test shaft unit. The crescent-shaped rolling groove 23 provides stable radial support for the test shaft unit while allowing the test shaft assembly unit to reciprocate axially without interference on the crescent-shaped rolling groove. A slider locking mechanism is provided at the lower end of the slider 19 to fix the slider 19 to the guide rail 22, and the slider locking mechanism is located on both sides of the contact area between the slider 19 and the guide rail 22. The slider locking mechanism can fix the slider 19 to the guide rail 22, ensuring that the slider 19 remains stationary during the test. Specifically, the slider locking mechanism applies a normal pressure perpendicular to the surface of the guide rail 22 to increase the static friction between the slider 19 and the guide rail 22, thereby locking and fixing the slider 19 to the guide rail 22. Without restricting the axial movement of the test shaft unit, it constrains the radial displacement of the test shaft unit, ensuring that the test shaft unit can stably reciprocate axially under the set eccentric or off-center load conditions. The relative sliding between the slider 19 and the guide rail 22 is only during the working condition setting stage. After the working condition setting is completed, the relative position of the slider 19 and the guide rail 22 is fixed and no longer participates in the motion constraint during the test operation. In a preferred embodiment, there are two sets of loading mechanisms.

[0032] In a preferred embodiment, the experimental apparatus further includes a signal acquisition and control unit 10, which is responsible for connecting to each sensor, collecting and processing data from each sensor during the test: the pressure sensor collects the pressure of the oil inside the test chamber, the temperature sensor 9 collects the temperature of the oil inside the test chamber, the first tension-compression sensor measures the axial load applied to the first test shaft by the linear drive unit, and the second tension-compression sensor 16 measures the axial force transmission from the first test shaft to the second test shaft inside the test shaft unit; the signal acquisition and control unit 10 is used to collect and process the data from each sensor.

[0033] The present invention can be adapted to various specifications of sealing rings by replacing the end caps 18 of the test shaft unit and the test cylinder unit of different specifications.

[0034] On the other hand, the present invention also provides a test method for a test device that simulates the eccentric loading condition of a sealing ring.

[0035] S1. Adjust the hinge unit and the lateral loading unit according to the target eccentricity or target off-center loading angle, adjust the test shaft unit to the corresponding offset position, and lock the hinge unit and the lateral loading unit.

[0036] Specifically, such as Figure 3 As shown, the adjustment steps for eccentric operation are as follows: Based on the test objective, the required target eccentricity h is determined. The extension of the hydraulic jacking mechanism on both sides of the loading mechanism is simultaneously adjusted to cause the test shaft unit to translate as a whole, resulting in a radial offset of the axis O of the test shaft unit relative to the axis O′ of the linear drive unit. Subsequently, the radial offset is precisely corrected by finely adjusting the position of the slider on the guide rail, ensuring that the test shaft unit remains parallel to the axis of the test cylinder unit. Throughout the adjustment process, the hinge unit moves accordingly, ensuring that the axes of the linear drive unit and the test shaft unit remain parallel. The actual radial offset of the test shaft unit is measured in real time. When the error between the actual radial offset and the target eccentricity is within the allowable range, the slider and hinge unit positions are locked, completing the setting of the eccentric working condition. In a preferred embodiment, a displacement sensor or dial indicator is used to measure the actual radial offset of the test shaft unit relative to the reference position. In another preferred embodiment, the displacement and height calibration relationship of the hydraulic jacking mechanism is used to measure the actual radial offset of the test shaft unit relative to the reference position.

[0037] Specifically, such as Figure 4 As shown, the adjustment steps for off-center load conditions are as follows: Based on the test objectives, the required target off-center load angle is determined. The extension amounts of the hydraulic jacking mechanisms on both sides of the loading mechanism are adjusted. When the extension amounts are inconsistent, the test shaft unit is driven to tilt centrally, forming the actual off-center load angle. Subsequently, the actual off-center load angle is finely corrected by adjusting the position of the slider on the guide rail. Throughout the adjustment process, the hinge unit moves accordingly to ensure coordinated movement between the linear drive unit and the test shaft unit. The actual off-center load angle of the test shaft unit is measured in real time. When the error between the actual off-center load angle and the target off-center load angle is within the allowable range, the slider and hinge unit positions are locked, completing the setting of the off-center load condition. Specifically, after the off-center load condition is set, the axis O′ of the test shaft unit forms a stable off-center load angle β relative to the axis O of the linear drive unit, which satisfies the following relationship: ; Where h1 and h2 are the heights of the support points of the loading mechanisms on both sides and the test shaft unit, respectively, and L is the axial distance between the support points of the loading mechanisms on both sides and the test shaft unit.

[0038] During the test operation phase, the linear drive unit drives the test shaft unit to reciprocate along the axial direction. The test shaft unit is supported radially by a crescent-shaped rolling groove and is not constrained by the guide rail in the axial direction, thus ensuring that the test shaft unit achieves smooth axial reciprocating motion while maintaining a preset off-center load angle β. The off-center load angle β is not formed by forcibly changing the axial movement direction of the test shaft unit, but by applying different radial position constraints to the test shaft unit at different axial positions, enabling it to form a stable and repeatable off-center load posture while maintaining its axial movement freedom.

[0039] After setting the eccentric or off-center load conditions, drive the test shaft unit to reciprocate at low speed and observe whether the test shaft unit maintains a stable support state throughout the entire stroke range. After confirming that there is no jamming, jumping or additional interference, proceed to the next test steps.

[0040] S2. Calibrate the inherent friction force. Without installing the sealing ring, start the linear drive unit to make the test shaft unit perform axial reciprocating motion under the set eccentricity or off-center loading angle. Use the first tension / compression sensor and the second tension / compression sensor to collect and record the axial force signal of the system at this time, as the reference data for subsequent friction force decoupling.

[0041] S3. Install the sealing ring to be tested, inject hydraulic oil and adjust the pressure to the set value; after the pressure and temperature parameters stabilize, start the linear drive unit to drive the test shaft unit to perform axial reciprocating motion along the preset eccentric or off-center load direction, and synchronously acquire multi-source signals through the servo motor, the first tension / compression sensor, the second tension / compression sensor, the pressure sensor, the temperature sensor and the drainage hole. Specifically: Axial force signals are collected by the first and second tension / compression sensors; leakage signals of the sealing ring are collected through the drainage hole; pressure and temperature signals inside the test chamber are collected by the pressure and temperature sensors; and motion signals of the test shaft unit are collected in real time by the linear drive unit.

[0042] S4. When the test reaches the preset termination condition, stop the test; based on the collected data throughout the process, calculate the key sealing performance indicators of the sealing ring under the eccentric or off-center load condition.

[0043] The experiment will be stopped immediately when any of the preset termination conditions are met: A significant and continuous leak was detected in the drainage hole; the sealing performance reached the preset failure criteria (such as leakage rate exceeding the threshold, abnormal fluctuation of friction, etc.); the cumulative running time or number of axial reciprocating strokes reached the set value.

[0044] Based on the data collected throughout the test, the basic performance parameters of the sealing ring can be directly calculated: leakage per unit time; steady-state leakage rate; and the relationship between leakage and pressure, temperature, and eccentric / eccentric load conditions.

[0045] Furthermore, through a comprehensive analysis of the basic performance parameters of the sealing ring, the key sealing behaviors and mechanisms of the sealing ring are as follows: the degradation law of the sealing performance of the sealing ring under eccentric working conditions; the changes in the contact and friction characteristics of the sealing ring under eccentric loading conditions; and the coupled influence of eccentricity or eccentric loading angle on leakage and friction.

[0046] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A test apparatus for simulating eccentric and eccentrically loaded sealing rings, characterized in that: It includes a linear drive unit, an articulation unit, a test shaft unit, a test cylinder unit, a lateral loading unit, and a hydraulic system unit; The linear drive unit includes a circular grating for detecting the amount of displacement caused by the linear drive unit driving the hinge unit; The articulated unit includes a first link, a second link, a first pin, and a second pin. The first end of the first link is rotatably connected to the connecting sleeve of the linear drive unit through the first pin, and the second end of the first link is rotatably connected to the first end of the second link through the second pin. The test shaft unit includes a first tension / compression sensor, a first test shaft, a second tension / compression sensor, and a second test shaft connected in sequence. The first tension / compression sensor is connected to the second end of the second connecting rod of the hinge unit. The first tension / compression sensor is used to measure the tension applied to the first test shaft by the linear drive unit. The second tension / compression sensor is used to measure the tension applied to the second test shaft by the first test shaft. The test cylinder unit includes a cylinder body and end caps located on both sides of the cylinder body along its axial direction; the top of the cylinder body is provided with an oil inlet for connection with the hydraulic system unit; the end caps are provided with end cap holes for the test shaft unit to pass through; and a sealing groove is provided on the inner circumferential surface of the end cap holes for installing the sealing ring to be tested. The lateral loading unit includes loading mechanisms symmetrically arranged on both sides of the outside of the test cylinder; each loading mechanism includes a guide rail, a slider, a hydraulic lifting mechanism, and a support; the lower end of the slider is slidably connected to the guide rail, and the upper end of the slider is in contact with the outer surface of the test shaft unit; the support and the hydraulic lifting mechanism are both located at the bottom of the guide rail and are rotatably connected to the guide rail.

2. The test apparatus for simulating eccentric and eccentric loading conditions of a sealing ring according to claim 1, characterized in that: The end cap is provided with a drainage hole. The opening at the first end of the drainage hole is located on the side of the sealing groove away from the inside of the cylinder body, and the opening at the second end of the drainage hole is connected to the outside of the cylinder body. The drainage hole can guide the oil seeping out from the leakage gap between the sealing ring to be tested and the test shaft unit to the outside of the cylinder body.

3. The test apparatus for simulating eccentric and eccentric loading conditions of a sealing ring according to claim 2, characterized in that: A pressure sensor is installed at the oil inlet, and a temperature sensor is installed inside the test cylinder unit.

4. The test apparatus for simulating eccentric and eccentric loading conditions of a sealing ring according to claim 3, characterized in that: The first connecting rod is provided with a first hinged locking hole corresponding to the position of the first pin, and the second connecting rod is provided with a second hinged locking hole corresponding to the position of the second pin; the first pin and the second pin can be tightened by the first hinged locking hole and the second hinged locking hole to limit the relative rotation between the linear drive unit and the first connecting rod, and between the first connecting rod and the second connecting rod.

5. The test apparatus for simulating eccentric and eccentric loading conditions of a sealing ring according to claim 3, characterized in that: The upper end of the slider is provided with a crescent-shaped rolling groove, which is in contact with the outer surface of the test shaft unit.

6. The test apparatus for simulating eccentric and eccentric loading conditions of a sealing ring according to claim 3, characterized in that: The lower end of the slider is provided with a slider fixing mechanism for fixing the slider to the guide rail, and the slider fixing mechanism is located on both sides of the contact area between the slider and the guide rail.

7. The test apparatus for simulating eccentric and eccentric loading conditions of a sealing ring according to claim 3, characterized in that: The linear drive unit includes a servo motor, a lead screw, a lead screw slide, a circular grating, and a connecting sleeve. The output end of the servo motor is fixedly connected to the lead screw, the lead screw is threadedly connected to the lead screw slide, the connecting sleeve is sleeved on the outside of the lead screw, and the lead screw slide is fixedly connected to the first end of the connecting sleeve. The second end of the connecting sleeve is rotatably connected to the first connecting rod through a first pin. The circular grating is sleeved on the outside of the lead screw.

8. A test method for a test apparatus used in any one of claims 3-7 to simulate eccentric and off-center loading conditions of a sealing ring, characterized in that: The specific steps are as follows: S1. Adjust the hinge unit and the lateral loading unit according to the target eccentricity or target off-center loading angle, adjust the test shaft unit to the corresponding offset position, and lock the hinge unit and the lateral loading unit. S2. Calibrate the inherent friction force. Without installing the sealing ring, start the linear drive unit to make the test shaft unit reciprocate axially under the set eccentricity or off-center loading angle. Use the first tension / compression sensor and the second tension / compression sensor to collect and record the axial force signal of the system at this time as the reference data for subsequent friction force decoupling. S3. Install the sealing ring to be tested, inject hydraulic oil and adjust the pressure to the set value; after the pressure and temperature parameters stabilize, start the linear drive unit to drive the test shaft unit to make axial reciprocating motion along the preset eccentric or off-center load direction, and synchronously acquire multi-source signals through the servo motor, the first tension and compression sensor, the second tension and compression sensor, the pressure sensor, the temperature sensor and the drainage hole. S4. When the test reaches the preset termination condition, stop the test; based on the collected data throughout the process, calculate the key sealing performance indicators of the sealing ring under the eccentric or off-center load condition.

9. The test method of the test apparatus for simulating eccentric and eccentric loading conditions of a sealing ring according to claim 8, characterized in that: The adjustment steps for eccentric operation are as follows: Based on the test objectives, the required target eccentricity is determined. The extension of the hydraulic jacking mechanism on both sides of the loading mechanism is simultaneously adjusted to cause the test shaft unit to translate as a whole, resulting in a radial offset of the test shaft unit's axis relative to the linear drive unit's axis. Subsequently, the radial offset is precisely corrected by finely adjusting the position of the slider on the guide rail, ensuring that the test shaft unit remains parallel to the test cylinder unit's axis. Throughout the adjustment process, the hinge unit moves accordingly, ensuring that the linear drive unit and the test shaft unit's axes remain parallel. The actual radial offset of the test shaft unit is measured in real time. When the error between the actual radial offset and the target eccentricity is within the allowable range, the slider and hinge unit positions are locked, completing the eccentricity setting.

10. The test method of the test apparatus for simulating eccentric and eccentric loading conditions of a sealing ring according to claim 8, characterized in that: The adjustment steps for off-center loading are as follows: Determine the required target off-center load angle based on the test objectives, and adjust the extension of the hydraulic jacking mechanism on both sides of the loading mechanism. When the extensions of the two mechanisms are inconsistent, the test shaft unit is driven to tilt in the center, forming the actual off-center load angle. Subsequently, the actual off-center load angle is finely corrected by adjusting the position of the slider on the guide rail. During the entire adjustment process, the hinge unit moves accordingly to ensure that the linear drive unit and the test shaft unit maintain coordinated movement. The actual off-center load angle of the test shaft unit is measured in real time. When the error between the actual off-center load angle and the target off-center load angle is within the allowable range, the slider and the hinge unit are locked to complete the setting of the off-center load condition.

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