A reciprocating sealing reliability test device and method under a multi-stress environment

Abstract

The application provides a reciprocating sealing reliability test device and method under a multi-stress environment, relates to the technical field of reciprocating sealing reliability testing of hydraulic cylinders for ships, and the device comprises a hydraulic cylinder, a load hydraulic system, a stress loading system, a clamp assembly and a detection system. The load hydraulic system is used for supplying oil to the hydraulic cylinder and adjusting the pressure and temperature of the oil. The stress loading system comprises a speed loading module and a vibration loading module. The clamp assembly is used for fixing the hydraulic cylinder, and the first-order natural frequency thereof is greater than 60 Hz. The detection system is used for collecting and monitoring sealing performance parameters of the hydraulic cylinder in a test process in real time. The application realizes coupling loading of speed, vibration and load, can simulate and reproduce the service environment of the hydraulic cylinder of the ship, the stable test is ensured through the optimized design of the clamp assembly, and the test efficiency is improved through the double-hydraulic-cylinder configuration.

Description

Technical Field

[0001] This invention relates to the field of reciprocating seal reliability testing technology for ship hydraulic cylinders, specifically to a reciprocating seal reliability testing device and method under multi-stress conditions. Background Technology

[0002] Ship hydraulic cylinders endure the combined effects of high-pressure oil, reciprocating friction, and continuous vibrations and load fluctuations generated by ship navigation during actual service, resulting in an extremely complex operating environment. Under this complex stress state, the performance degradation of reciprocating seals exhibits nonlinear characteristics, and the failure mechanism is difficult to predict. Existing domestic testing equipment has significant shortcomings in simulating the real service environment of ship hydraulic cylinders, mainly in the following aspects:

[0003] First, existing testing devices are mostly based on simplified or idealized experimental conditions, which cannot fully reproduce the multi-stress coupling environment faced by hydraulic cylinders in actual service. Most devices can only simulate single or partial operating parameters such as pressure, temperature, and reciprocating speed, lacking consideration of vibration stress and other stress coupling effects. This leads to a large deviation between test results and actual service conditions, severely restricting in-depth research on the degradation mechanism of reciprocating seal performance and the improvement of the accuracy of life prediction models.

[0004] Secondly, the performance changes of reciprocating seals under complex operating conditions often exhibit minute, transient, and nonlinear characteristics, such as small fluctuations in friction, gradual changes in seal wear, and phased increases in leakage rate. These subtle changes place extremely high demands on the measurement accuracy, data sampling frequency, and signal processing capabilities of the testing equipment. However, the shortcomings of existing testing equipment in terms of sensor accuracy and real-time data processing algorithms make it difficult to achieve highly sensitive monitoring and accurate analysis of the seal performance degradation process, thus limiting the accurate determination of the failure mechanism of reciprocating seals.

[0005] Furthermore, low testing efficiency is also a prominent problem with existing devices. Traditional testing methods typically employ a single-sample, one-by-one testing approach, resulting in long testing cycles that cannot meet the needs of batch verification and rapid evaluation, thus hindering the progress of seal reliability research and product development.

[0006] Chinese patent document CN105673621B discloses a multi-condition integrated simulation test system for reciprocating seals of aircraft actuators. It discloses a technical solution that uses a vibration platform, a high and low temperature environment chamber, and a hydraulic system to simulate high pressure, wide temperature range, variable speed, and airborne vibration conditions. It achieves the technical effects of multi-condition integrated simulation and vibration isolation. However, this solution is designed for aircraft actuators and focuses on vibration isolation rather than multi-stress coupling loading. It also adopts a single-sample test method, which has low test efficiency and cannot meet the accurate simulation requirements of ship hydraulic cylinders under extreme multi-stress coupling conditions such as high pressure, vibration, and load fluctuation.

[0007] Chinese patent document CN109357960B discloses a method and test device for testing the service fatigue performance of hydraulic reciprocating seals. It discloses a technical solution that uses fiber optic strain sensors to monitor contact stress and calculates fatigue state by failure probability. This achieves the technical effect of testing the fatigue life of seals and judging failure state. However, this solution does not involve vibration stress simulation and can only simulate some working condition parameters such as reciprocating speed, load and temperature. Moreover, it uses a single contact stress parameter for monitoring, which cannot fully reflect the complex performance degradation process of reciprocating seals in ship hydraulic cylinders under multi-stress coupling environment. Summary of the Invention

[0008] The purpose of this invention is to provide a test device and method for the reliability of reciprocating seals under multi-stress conditions, which has the ability to perform multi-stress coupling loading, accurately simulates the complex working conditions of hydraulic cylinders in actual service in a ship environment, improves data acquisition and analysis capabilities, and improves test efficiency.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A test apparatus for the reliability of reciprocating seals under multi-stress conditions, comprising:

[0011] A hydraulic cylinder includes a cylinder barrel and a piston rod connected in sequence, and a seal is provided inside the cylinder barrel;

[0012] A load hydraulic system is used to supply oil to the hydraulic cylinder and regulate the pressure and temperature of the oil. The load hydraulic system applies load stress to the hydraulic cylinder through pressure regulation.

[0013] The stress loading system includes a velocity loading module and a vibration loading module. The velocity loading module is used to drive the piston rod to reciprocate, and the vibration loading module is used to apply vibration stress to the seal.

[0014] A clamping assembly for fixing the hydraulic cylinder, wherein the first-order natural frequency of the clamping assembly is greater than 60Hz;

[0015] The detection system is used to collect and monitor the sealing performance parameters of the hydraulic cylinder in real time during the test process;

[0016] The hydraulic cylinder is mounted on the clamping assembly, the stress loading system is connected to both the hydraulic cylinder and the clamping assembly, and the detection system is connected to the hydraulic cylinder.

[0017] Furthermore, the hydraulic cylinder includes a first hydraulic cylinder and a second hydraulic cylinder. The piston rod end of the first hydraulic cylinder is connected to the piston rod end of the second hydraulic cylinder in sequence through a tension / compression sensor, a threaded rod, and a flange nut. The piston rod-less ends of the first hydraulic cylinder and the piston rod-less ends of the second hydraulic cylinder are respectively fixed at both ends of the clamping assembly.

[0018] Furthermore, the speed loading module includes a servo motor, a frequency converter, and a speed control device, wherein the servo motor is connected to the hydraulic cylinder in sequence through the frequency converter and the speed control device.

[0019] Furthermore: the vibration loading module includes a vibration table, and the clamp assembly is fixed on the vibration table.

[0020] Furthermore, the vibration table generates a vibration frequency range of 16Hz-60Hz.

[0021] Furthermore: the load hydraulic system includes an oil tank, an oil pump, a filter, a heater, a cooling fan, and an electro-hydraulic servo valve; the heater and the cooling fan are respectively connected to the oil tank, the oil tank is connected to the inlet of the oil pump through the filter, and the outlet of the oil pump is connected to the cylinder of the hydraulic cylinder through the electro-hydraulic servo valve.

[0022] Furthermore, the detection system includes interconnected sensors and a data acquisition and analysis unit, with the sensors mounted on a hydraulic cylinder.

[0023] Furthermore: the sensor includes a vibration sensor, an oil temperature sensor, and a tension / compression sensor; the vibration sensor is installed on the vibration loading module, the clamp assembly, and the hydraulic cylinder; the oil temperature sensor is installed on the oil pipeline of the load hydraulic system; the tension / compression sensor is installed between the piston rod end of the first hydraulic cylinder and the piston rod end of the second hydraulic cylinder, and serves as a connection.

[0024] Furthermore, the clamp assembly includes a first fixing plate, a second fixing plate, and a plurality of load-connecting structural rods. The first fixing plate and the second fixing plate are fixedly connected by the load-connecting structural rods. The first fixing plate is provided with a fixing lug support, and the second fixing plate is provided with a fixing structure.

[0025] A method for testing the reliability of reciprocating seals applied to the above-mentioned device includes the following steps:

[0026] S1: Install the hydraulic cylinder to be tested into the fixture assembly;

[0027] S2: Adjust the pressure and temperature of the hydraulic fluid to a preset value using the load hydraulic system;

[0028] S3: Apply velocity stress and vibration stress to the hydraulic cylinder through the stress loading system, and apply load stress to the hydraulic cylinder by adjusting the oil pressure through the load hydraulic system;

[0029] S4: The sealing performance parameters of the hydraulic cylinder are collected in real time through the detection system;

[0030] S5: Evaluate the performance degradation status and reliability of reciprocating seals based on the collected sealing performance parameters.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] I. This invention, by constructing a three-stress coupled loading capability including a speed loading module, a vibration loading module, and a load hydraulic system, can accurately simulate the synergistic effect of multiple stresses such as high-pressure oil, reciprocating motion, vibration load, and load fluctuation that ship hydraulic cylinders endure in actual service. It breaks through the limitation of existing devices that can only simulate single or partial working parameters, so that the test results truly reflect the actual service performance of ship reciprocating seals, and provide reliable data support for the study of performance degradation mechanisms and life prediction.

[0033] Second, this invention employs a configuration of two hydraulic cylinders connected vertically to achieve parallel testing of dual samples. Compared with the traditional single-sample testing method, this significantly shortens the testing cycle, greatly improves testing efficiency, and accelerates the reliability verification of seals and the product development process. The detection system collects and calculates relevant sealing performance parameters such as leakage, friction, temperature, and pressure in real time through multiple sensors. It can comprehensively monitor the performance degradation process of seals under multi-stress coupling environments, providing rich data support for seal life prediction and reliability assessment, and more accurately reflecting the actual working state and performance change trend of seals.

[0034] Third, through optimized design, this invention enables the first-order natural frequency of the fixture assembly to reach 74Hz and the strength to meet the requirements of shipboard environmental conditions, ensuring the stability of the device when simulating ship vibration environment, reducing the error of test results caused by the characteristics of the fixture itself, and further improving the reliability of the test. Attached Figure Description

[0035] Figure 1 This invention provides a schematic diagram of the load pressurization system of a reciprocating seal reliability testing device under multi-stress conditions.

[0036] Figure 2 A schematic diagram of the combined structure of the fixture assembly, hydraulic cylinder and vibration table in a reciprocating seal reliability testing device under multi-stress environment provided by the present invention;

[0037] Figure 3This is a schematic diagram of the fixture assembly in a reciprocating seal reliability testing device under multi-stress conditions provided by the present invention.

[0038] Figure 4 A schematic diagram of the connection structure of the hydraulic cylinder in a reciprocating seal reliability testing device under multi-stress environment provided by the present invention;

[0039] Figure 5 The flowchart of a reciprocating seal reliability test method under multi-stress environment provided by the present invention.

[0040] In the picture:

[0041] 1. Vibration table; 2. First fixed plate; 3. Fixed lug support; 4. Load connection structure rod; 5. First hydraulic cylinder; 6. Tension and compression sensor; 7. Second hydraulic cylinder; 8. Fixed structure; 9. Oil tank; 10. Oil pump; 11. Filter; 12. Heater; 13. Cooling fan; 14. Second fixed plate. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] Example 1

[0045] like Figures 1-4 As shown, the present invention provides a reciprocating seal reliability testing device under multi-stress environment, including a hydraulic cylinder, a load hydraulic system, a stress loading system, a fixture assembly, and a testing system.

[0046] The hydraulic cylinder includes a cylinder barrel and a piston rod, with seals installed inside the cylinder barrel. A load hydraulic system supplies hydraulic fluid to the cylinder and regulates its pressure and temperature. A stress loading system includes a velocity loading module and a vibration loading module. The velocity loading module drives the piston rod in reciprocating motion, while the vibration loading module applies vibration stress to the seals. A fixture assembly secures the hydraulic cylinder; its first-order natural frequency is greater than 60Hz. A detection system collects and monitors the sealing performance parameters of the hydraulic cylinder in real time during the test. The hydraulic cylinder is mounted on the fixture assembly. The load hydraulic system applies load stress to the cylinder through pressure regulation. The stress loading system is connected to both the hydraulic cylinder and the fixture assembly, and the detection system is connected to the hydraulic cylinder. Through the synergistic action of the velocity loading module, the vibration loading module, and the load hydraulic system, comprehensive testing of the reciprocating seals under coupled velocity stress, vibration stress, and load stress is achieved, accurately simulating the actual service conditions of ship hydraulic cylinders.

[0047] In one specific embodiment of this invention, the hydraulic cylinders include a first hydraulic cylinder 5 and a second hydraulic cylinder 7. The rod end of the first hydraulic cylinder 5 is connected to a threaded rod via a tension / compression sensor 6. The threaded rod is connected to the rod end of the second hydraulic cylinder 7 via a flange nut. The rodless ends of the first and second hydraulic cylinders are respectively fixed to both ends of the clamp assembly. The tension / compression sensor 6 has internal threads at both ends, and the rod ends of the two hydraulic cylinders are securely connected via threaded connections. The two hydraulic cylinders are arranged vertically and work synchronously during the test, enabling parallel testing of two samples, significantly shortening the test cycle and improving test efficiency.

[0048] In one specific embodiment of this example, the speed loading module includes a servo motor, a frequency converter, and a speed control device. The servo motor is connected to the hydraulic cylinder in sequence through the frequency converter and the speed control device. By controlling the rotational speed of the servo motor, the speed is transmitted to the piston rod via the frequency converter and the speed control device, thereby achieving precise control of the reciprocating speed of the piston rod, with a speed range of 0.005 m / s to 0.1 m / s.

[0049] In one specific embodiment of this invention, the vibration loading module includes a vibration table 1, and a clamp assembly is fixed on the vibration table 1. The vibration table 1 drives the clamp assembly and hydraulic cylinder to vibrate as a whole, simulating the vibration environment in actual working conditions.

[0050] In one specific embodiment of this example, the vibration table 1 generates a vibration frequency range of 16Hz to 60Hz. The vibration table 1 has adjustable vibration frequency, amplitude, and waveform parameters, and the vibration waveform is a sine wave, which meets the simulation requirements of the ship vibration environment.

[0051] In one specific embodiment of this example, the load hydraulic system includes an oil tank 9, an oil pump 10, a filter 11, a heater 12, a cooling fan 13, and an electro-hydraulic servo valve. The heater 12 and the cooling fan 13 are respectively connected to the oil tank 9 for regulating the oil temperature. The oil tank 9 is connected to the inlet of the oil pump 10 through the filter 11, and the outlet of the oil pump 10 is connected to the rod chamber and / or rodless chamber of the hydraulic cylinder through the electro-hydraulic servo valve. The electro-hydraulic servo valve precisely controls the oil pressure entering each chamber of the hydraulic cylinder to apply load stress; the pressure adjustment range is 1 MPa to 25 MPa. The heater 12 and the cooling fan 13 work in coordination to precisely regulate the oil temperature within a preset range.

[0052] In one specific embodiment of this invention, the detection system includes a sensor and a data acquisition and analysis unit connected in sequence, with the sensor mounted on a hydraulic cylinder. The sensor collects sealing performance-related parameters in real time, and the data acquisition and analysis unit converts the collected analog signals into digital signals and processes and analyzes them.

[0053] In one specific embodiment of this invention, the sensors include a vibration sensor, an oil temperature sensor, and a tension / compression sensor 6. The vibration sensor is installed on the vibration loading module, the fixture assembly, and the hydraulic cylinder to monitor the transmission of vibration stress within the testing apparatus. The oil temperature sensor is installed on the oil pipeline of the load hydraulic system to monitor changes in oil temperature in real time. The tension / compression sensor 6 is installed between the rod end of the first hydraulic cylinder 5 and the rod end of the second hydraulic cylinder 7, serving both as a connection and monitoring the tension / compression load force between the two hydraulic cylinders in real time. Through the cooperation of multiple types of sensors, comprehensive monitoring of multiple stress parameters such as speed, vibration, and load during the test is achieved.

[0054] In one specific embodiment of this invention, the fixture assembly includes a first fixing plate 2, a second fixing plate 14, and multiple load-connecting structural rods 4. The first fixing plate 2 and the second fixing plate 14 are fixedly connected by the load-connecting structural rods 4. The rodless end of the first hydraulic cylinder 5 is fixed to the first fixing plate 2, and the rodless end of the second hydraulic cylinder 7 is fixed to the second fixing plate 14. The entire structure is mounted on the vibration table 1 via the first fixing plate 2. The first fixing plate 2 is provided with a fixing lug support 3 for fixing the first hydraulic cylinder 5. The second fixing plate 14 is provided with a fixing structure 8 for improving the overall stability of the fixture assembly. The fixture assembly is made of high-strength steel and, through reasonable structural design, possesses high rigidity and lightweight characteristics. Testing shows that the first natural frequency of this fixture assembly reaches 74Hz, and its static load strength meets the requirements of shipboard environmental conditions. It can effectively avoid resonance in vibration tests ranging from 16Hz to 60Hz, ensuring the stability of the test platform.

[0055] Example 2

[0056] like Figure 5 As shown, the present invention also provides a method for testing the reliability of reciprocating seals using the above-mentioned device, comprising the following steps. First, the hydraulic cylinder to be tested is installed in a fixture assembly. The rod ends of the lower and upper hydraulic cylinders are connected together by tension and pressure sensors. The rodless ends of the two hydraulic cylinders are fixed to the upper and lower ends of the fixture, respectively. The entire fixture and the hydraulic cylinder test piece are placed on a vibration table via a lower fixed platform. Then, the pressure and temperature of the hydraulic fluid are adjusted to preset values ​​through a load hydraulic system. The oil ports of the rod and rodless chambers of the upper and lower hydraulic cylinders are connected to the electro-hydraulic servo valves in the load hydraulic system via high-pressure oil pipes. Next, velocity stress and vibration stress are applied to the hydraulic cylinder through a stress loading system. Load stress is applied to the hydraulic cylinder by adjusting the hydraulic fluid pressure through the load hydraulic system. The reciprocating speed of the test piece is achieved by precise control of the hydraulic oil flow rate. Vibration is precisely simulated by adjusting the vibration frequency and amplitude as needed by the vibration table. The load is applied by finely adjusting the oil pressure using the electro-hydraulic servo valve. Simultaneously, the sealing performance parameters of the hydraulic cylinder are collected in real time through the detection system, including data such as the load, vibration frequency and acceleration, reciprocating speed, hydraulic oil leakage, and seal wear of the test hydraulic cylinder. Finally, the performance degradation state and reliability of the reciprocating seal are evaluated based on the collected sealing performance parameters, providing a basis for life prediction and reliability design of reciprocating seals for ship hydraulic cylinders.

[0057] In one specific embodiment of this invention, velocity stress is applied by adjusting the servo motor speed, vibration stress is applied by adjusting the vibration frequency and amplitude of the vibration table, and load stress is applied by adjusting the hydraulic pressure through an electro-hydraulic servo valve. These three stresses are independently controllable and applied synergistically, realistically replicating the service environment of ship hydraulic cylinders under multi-stress coupling conditions. After the two test hydraulic cylinders are securely connected at their rod ends, they are subjected to upward and reciprocating motion under the action of the test bench. The two hydraulic cylinders complete the performance degradation test of the seals within the same test cycle.

[0058] During the test, the two hydraulic cylinders completed the wear failure test of the seals within the same test cycle. Using the above-mentioned test apparatus and method, the service environment of ship hydraulic cylinders under multiple stress coupling conditions such as high pressure, vibration, and load fluctuation can be realistically simulated, obtaining fatigue life data of reciprocating seals under specific service conditions, providing a basis for the reliability design of hydraulic reciprocating seals.

[0059] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A device for testing the reliability of reciprocating seals under a multi-stress environment, characterized in that: include; A hydraulic cylinder includes a cylinder barrel and a piston rod connected in sequence, and a seal is provided inside the cylinder barrel; A load hydraulic system is used to supply oil to the hydraulic cylinder and regulate the pressure and temperature of the oil. The load hydraulic system applies load stress to the hydraulic cylinder through pressure regulation. A stress loading system includes a speed loading module and a vibration loading module. The speed loading module drives the piston rod to reciprocate, and the vibration loading module applies vibration stress to the seal. The speed loading module includes a servo motor, a frequency converter, and a speed control device. The servo motor is connected to the piston rod of the hydraulic cylinder in sequence through the frequency converter and the speed control device. A clamping assembly for fixing the hydraulic cylinder, wherein the first-order natural frequency of the clamping assembly is greater than 60Hz; The detection system is used to collect and monitor the sealing performance parameters of the hydraulic cylinder in real time during the test process; The hydraulic cylinder is mounted on the clamping assembly, the stress loading system is connected to both the hydraulic cylinder and the clamping assembly, and the detection system is connected to the hydraulic cylinder. The hydraulic cylinder includes a first hydraulic cylinder and a second hydraulic cylinder. The piston rod end of the first hydraulic cylinder is connected to the piston rod end of the second hydraulic cylinder in sequence through a tension / compression sensor, a threaded rod, and a flange nut. The piston rod-less ends of the first hydraulic cylinder and the piston rod-less ends of the second hydraulic cylinder are respectively fixed at both ends of the clamping assembly. The vibration loading module includes a vibration table, and the clamp assembly is fixed on the vibration table.

2. The device according to claim 1, characterized in that: The vibration table generates a vibration frequency range of 16Hz-60Hz.

3. The device according to claim 1, wherein: The load hydraulic system includes an oil tank, an oil pump, a filter, a heater, a cooling fan, and an electro-hydraulic servo valve; the heater and the cooling fan are respectively connected to the oil tank, the oil tank is connected to the inlet of the oil pump through the filter, and the outlet of the oil pump is connected to the cylinder of the hydraulic cylinder through the electro-hydraulic servo valve.

4. The device according to claim 1, characterized in that: The detection system includes interconnected sensors and data acquisition and analysis units.

5. The device according to claim 4, characterized in that: The sensors include a vibration sensor, an oil temperature sensor, and a tension / compression sensor; the vibration sensor is installed on the vibration loading module, the clamp assembly, and the hydraulic cylinder; the oil temperature sensor is installed on the oil pipeline of the load hydraulic system; the tension / compression sensor is installed between the piston rod end of the first hydraulic cylinder and the piston rod end of the second hydraulic cylinder, and serves as a connection.

6. The device according to claim 1, wherein: The clamp assembly includes a first fixing plate, a second fixing plate, and a plurality of load-connecting structural rods. The first fixing plate and the second fixing plate are fixedly connected by the load-connecting structural rods. The first fixing plate is provided with a fixing lug support, and the second fixing plate is provided with a fixing structure.

7. A reciprocating seal reliability test method using the device according to any one of claims 1 to 6, characterized by, Includes the following steps: S1: Install the hydraulic cylinder to be tested into the fixture assembly; S2: Adjust the pressure and temperature of the hydraulic fluid to a preset value using the load hydraulic system; S3: Apply velocity stress and vibration stress to the hydraulic cylinder through the stress loading system, and apply load stress to the hydraulic cylinder by adjusting the oil pressure through the load hydraulic system; S4: The sealing performance parameters of the hydraulic cylinder are collected in real time through the detection system; S5: Evaluate the performance degradation status and reliability of reciprocating seals based on the collected sealing performance parameters.

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