Piston ring fatigue testing machine and testing method

Abstract

The invention relates to the technical field of material fatigue testing equipment, in particular to a piston ring fatigue testing machine and method, and the piston ring fatigue testing machine comprises a test bed, a constant-pressure servo hydraulic pump station and an electrical control system. According to the piston ring fatigue testing machine and the testing method, the force servo valve and the high-precision sensor are adopted, the loading force control precision is + / -0.5% FS, the displacement measurement precision is + / -0.01 mm, data are reliable, and the testing precision is high; the double-stand-column structure and the adjustable clamp are compatible with the piston ring with the outer diameter of 300-1000 mm, and adaptability is high; the integration of parameter setting, real-time monitoring and data processing is realized through full-digital control software, human intervention is reduced, the test repeatability is improved, and the automation degree is high; the hydraulic system follows the pressure, the cooling system guarantees long-term continuous operation, the low-noise design is suitable for the laboratory environment, and operation is stable.

Description

Technical Field

[0001] This invention relates to the field of material fatigue testing equipment technology, and in particular to a piston ring fatigue testing machine and testing method. Background Technology

[0002] Large-diameter piston rings are widely used in heavy machinery, marine engines, and other fields, and their fatigue performance directly affects the lifespan and reliability of these devices. Existing fatigue testing machines are mostly designed for small, standard specimens, making it difficult to adapt to the special dimensions and stress requirements of large-diameter piston rings. Traditional equipment suffers from low loading accuracy, unstable clamping, and insufficient automation, resulting in poor repeatability of test data and inaccurate simulation of operating conditions. Therefore, there is an urgent need for a high-precision, high-efficiency fatigue testing device specifically designed for large-diameter piston rings. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that the existing technology suffers from low testing accuracy, poor adaptability, and insufficient automation.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a large-diameter piston ring fatigue testing machine, including a test bench, a constant pressure servo hydraulic pump station and an electrical control system; The test bench is a double-column frame structure, including a double-column main frame, a linear actuator, a moving crossbeam, a worktable, a load sensor, and a displacement sensor. The constant pressure servo hydraulic pump station includes a base plate, oil tank, oil pump motor unit, valve block, pipeline, cooling system, hydraulic system and oil source system. The hydraulic system adopts a differential circuit, and the oil source system is a pressure following system. The constant pressure servo hydraulic pump station is equipped with a force servo valve, a low noise plunger pump, a precision oil filter and an overflow valve. The electrical control system includes a computer console, an industrial control computer, fully digital control software, a data acquisition module, and a servo controller. The industrial control computer is communicatively connected to the data acquisition module, the servo controller, and the constant pressure servo hydraulic pump station. The fully digital control software enables test parameter setting, real-time control, and data processing.

[0005] The linear actuator consists of an actuator body and a hydraulic control module. The hydraulic control module is connected to the valve block of the constant pressure servo hydraulic pump station through a high-pressure pipeline. The output force range is 0-100kN and the dynamic response frequency is 0.1-15Hz.

[0006] The lifting accuracy of the moving crossbeam is ±0.1mm, and it is controlled in a closed loop by a hydraulic cylinder and a position sensor.

[0007] The fully digital control software includes a parameter setting module, a real-time monitoring module, a data storage module, and a fault diagnosis module. The parameter setting module supports preset loading force, loading frequency, and number of cycles. The real-time monitoring module dynamically displays the force-displacement curve, test progress, and equipment status. The fault diagnosis module can alarm and automatically shut down the machine in case of sensor abnormalities or hydraulic system overpressure.

[0008] The effective width between the columns of the dual-column main frame is not less than 530mm, and the height of the test space is not less than 1000mm. The moving crossbeam is driven by a hydraulic cylinder to lift and lower, which is used to adjust the test space. The linear actuator is installed on the moving crossbeam and forms a loading force frame with the worktable. Its piston rod has a built-in displacement sensor. The load sensor is installed on the upper surface of the worktable for real-time detection of the test load.

[0009] The test method based on the large-diameter piston ring fatigue testing machine according to any one of claims 1-5 includes the following steps: Step 1: Preparation and inspection before use, check hydraulic oil, oil pipes, cables and power connections; Step 2: Install the test specimen. Place the large-diameter piston ring on the test fixture on the workbench, adjust the moving beam to align the piston rod of the linear actuator with the piston ring surface, and clamp the piston ring. Step 3: Parameter setting. Input test parameters, including loading force, loading frequency, number of cycles, and test termination conditions, through the fully digital control software. Step 4: System startup and debugging. Start the constant pressure servo hydraulic pump station, preload and check sensor feedback to ensure the system is normal. Step 5: Start the test, start the test program, control the linear actuator to perform static or dynamic loading, and the data acquisition module synchronously acquires force and displacement signals; Step 6: Test termination and data processing. When the termination conditions are met, the system will automatically stop, generate a test report, and store the data.

[0010] The beneficial effects of this invention are: (1) The piston ring fatigue testing machine and testing method of the present invention adopts a force servo valve and a high-precision sensor, with a loading force control accuracy of ±0.5%FS and a displacement measurement accuracy of ±0.01mm. The data is reliable and the test accuracy is high. (2) The double column structure and adjustable clamp are compatible with piston rings with an outer diameter of 300-1000mm, and have strong adaptability; (3) The parameter setting, real-time monitoring and data processing are integrated through fully digital control software, which reduces human intervention, improves test repeatability and has a high degree of automation; (4) The hydraulic system pressure follows and the cooling system ensures long-term continuous operation. The low-noise design is suitable for laboratory environments and the operation is stable. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0012] Figure 1 This is a schematic diagram of the structure of the test bench in this invention.

[0013] Figure 2 This is the front view of the test bench in this invention.

[0014] Figure 3 This is a schematic diagram of the constant pressure servo hydraulic pump station in this invention.

[0015] Figure 4 This is a schematic diagram of the electrical control system in this invention. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0017] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] Figure 1 , Figure 2 and Figure 3 The large-diameter piston ring fatigue testing machine shown includes a test bench, a constant pressure servo hydraulic pump station, and an electrical control system; The test bench is a double-column frame structure made of 45# steel with a chrome-plated surface. It includes a double-column main frame 1, a linear actuator 2, a moving crossbeam 3, a worktable 4, a load sensor 5, and a displacement sensor 6. The effective width between the columns of the double-column main frame 1 is 530mm, and the test space height is 1000mm. The moving crossbeam 3 is driven by a hydraulic cylinder with a lifting accuracy of ±0.1mm. The linear actuator 2 has a rated output force of 100kN and a dynamic frequency of 0.1-15Hz, with a displacement sensor built into the piston rod. The worktable 4 is equipped with a T-slot fixture, and the load sensor 5 has a range of 0-100kN and an accuracy of 0.1%. The constant pressure servo hydraulic pump station includes a base plate, an oil tank 7, an oil pump motor unit, a valve block 8, pipelines, a cooling system 71, a hydraulic system, and an oil source system. The hydraulic system adopts a differential circuit, and the oil source system is a pressure following system. The constant pressure servo hydraulic pump station is equipped with a force servo valve, a low-noise plunger pump (noise ≤65dB), a precision oil filter (filtration accuracy ≤5μm), and an overflow valve (set pressure 35MPa). The oil tank is made of 200L stainless steel. The electrical control system includes a computer console 9, an industrial control computer 10, fully digital control software, a data acquisition module, and a servo controller. The industrial control computer 10 communicates with the data acquisition module, the servo controller, and the constant pressure servo hydraulic pump station, and uses the fully digital control software to set test parameters, perform real-time control, and process data. The electrical control system is centered on the industrial control computer 10, equipped with a data acquisition card, a servo controller, and fully digital control software. The software supports parameter presets, real-time curve display, data storage, and fault diagnosis, and has overload, overtravel, and over-temperature protection functions.

[0019] The linear actuator 2 consists of an actuator body and a hydraulic control module. The hydraulic control module is connected to the valve block 8 of the constant pressure servo hydraulic pump station through a high-pressure pipeline. The output force range is 0-100kN and the dynamic response frequency is 0.1-15Hz.

[0020] The lifting accuracy of the moving crossbeam 3 is ±0.1mm, and it is controlled in a closed loop by a hydraulic cylinder and a position sensor.

[0021] The fully digital control software includes a parameter setting module, a real-time monitoring module, a data storage module, and a fault diagnosis module. The parameter setting module supports preset loading force, loading frequency, and number of cycles. The real-time monitoring module dynamically displays the force-displacement curve, test progress, and equipment status. The fault diagnosis module can alarm and automatically shut down the machine in case of sensor abnormalities or hydraulic system overpressure.

[0022] The effective width between the columns of the dual-column main frame is not less than 530mm, and the height of the test space is not less than 1000mm. The moving crossbeam 3 is driven by a hydraulic cylinder to lift and lower, which is used to adjust the test space. The linear actuator 2 is installed on the moving crossbeam 3 and forms a loading force frame with the workbench 4. Its piston rod has a built-in displacement sensor, and the load sensor 5 is installed on the upper end face of the workbench 4 for real-time detection of the test load.

[0023] Example of test method Taking the dynamic fatigue test of a piston ring with an outer diameter of 520mm and a thickness of 16mm as an example: Check the hydraulic oil, lines, and power supply; Install the piston rings onto the clamp, adjust the height of the moving crossbeam 3, and set the clamping force to 50 N·m. Set dynamic test parameters: alternating force 10-50kN, frequency 10Hz, number of cycles 10 6 Second-rate; Start the pump station and preload the calibration sensors; During the test, the system automatically controlled alternating loading and collected force-displacement data; The machine will automatically stop when the displacement changes by more than 5 mm and generate a report, including fatigue life and maximum deformation.

[0024] The test method based on the large-diameter piston ring fatigue testing machine according to any one of claims 1-5 includes the following steps: Step 1: Preparation and inspection before use, check hydraulic oil, oil pipes, cables and power connections; Step 2: Install the sample, place the large-diameter piston ring on the test fixture of the workbench 4, adjust the moving crossbeam 3 to align the piston rod of the linear actuator 2 with the piston ring surface, and clamp the piston ring. Step 3: Parameter setting. Input test parameters, including loading force, loading frequency, number of cycles, and test termination conditions, through the fully digital control software. Step 4: System startup and debugging. Start the constant pressure servo hydraulic pump station, preload and check sensor feedback to ensure the system is normal. Step 5: Start the test, start the test program, control the linear actuator 2 to perform static or dynamic loading, and the data acquisition module synchronously acquires force and displacement signals; Step 6: Test termination and data processing. When the termination conditions are met, the system will automatically stop, generate a test report, and store the data.

[0025] Working principle of the equipment The equipment is centered around an industrial control computer 10 in the electrical control system, which coordinates the collaborative work of the test bench and the constant pressure servo hydraulic pump station. In the constant pressure servo hydraulic pump station, the oil tank 7 stores hydraulic oil. The oil pump motor unit pressurizes the hydraulic oil and delivers it to the valve block 8. The pressure and flow are precisely regulated by the force servo valve, and then delivered to the hydraulic control module of the linear actuator 2 through the high-pressure pipeline to provide loading power to the linear actuator 2. The hydraulic system adopts a differential circuit to improve the loading response speed. The pressure following function of the oil source system can match the load pressure in real time to avoid energy waste. The precision oil filter can control the hydraulic oil filtration accuracy to ≤5μm to ensure the life of hydraulic components. The relief valve is set at a pressure of 35MPa to prevent system overpressure. The cooling system maintains the hydraulic oil temperature at 30-55℃ to avoid the degradation of oil performance. The double-column main frame 1 of the test bench is welded from No. 45 steel, providing a stable test support structure. The moving crossbeam 3 is driven by a hydraulic cylinder and, in conjunction with a position sensor, achieves lifting accuracy of ±0.1mm. The test space height can be adjusted according to the piston ring specifications. The linear actuator 2 is mounted on the moving crossbeam 3, forming a loading force application frame with the workbench 4. The displacement sensor 6 built into its piston rod can collect the displacement change signal of the piston ring in real time, while the load sensor 5 (range 0-100kN, accuracy 0.1 grade) on the upper surface of the workbench 4 detects the magnitude of the loading force in real time. The computer operating console 9 of the electrical control system allows for interactive operation by the operator. The fully digital control software can realize test parameter preset, real-time monitoring of force-displacement curves and equipment status, automatic data storage, and fault diagnosis. The data acquisition module converts the signals from the load sensor 5 and the displacement sensor 6 and transmits them to the industrial control computer 10. The servo controller adjusts the loading action of the linear actuator 2 according to the instructions of the industrial control computer 10, ultimately realizing the static or dynamic fatigue test of large-diameter piston rings.

[0026] III. Equipment Working Process Preparation phase: First, check whether the hydraulic oil level in the oil tank 7 of the constant pressure servo hydraulic pump station is sufficient, and confirm whether the oil pipes and cables are intact and the power supply connection is correct; then check whether the components of the test bench, such as the double column main frame 1, linear actuator 2, and moving crossbeam 3, are in normal condition.

[0027] Sample installation: Place the large-diameter piston ring horizontally on the test fixture of the workbench 4. Send instructions through the industrial control computer 10 to control the raising and lowering of the moving crossbeam 3, so that the distance between the piston rod of the linear actuator 2 and the piston ring surface is adjusted to about 10mm. Then rotate the fixture adjusting bolt to make the polyurethane clamping plate in close contact with the outer circle of the piston ring. Use a torque wrench to control the clamping force at 50N·m to ensure that the piston ring does not slide radially.

[0028] Parameter setting: The operator opens the fully digital control software on the computer console 9, selects the test mode (static or dynamic), and inputs the test parameters, including the loading force range (e.g., 10-50kN), loading frequency (e.g., 10Hz), and number of cycles (e.g., 10). 6 After setting the parameters (times) and test termination conditions (such as displacement sudden change > 5mm), save them to the system.

[0029] System debugging: Start the constant pressure servo hydraulic pump station, the oil pump motor unit starts to work, and the hydraulic system pressure rises to 5MPa; control the linear actuator 2 to perform 3 preloads (load force 0-30kN), observe the linearity of the force-displacement curve through the fully digital control software, if the error is > ±0.5%, then correct the parameters of load sensor 5 and displacement sensor 6 through the "sensor calibration" function until the feedback signal is normal.

[0030] Test run: After the pre-debugging is successful, the test program is started. The industrial control computer 10 drives the force servo valve through the servo controller and adjusts the linear actuator 2 to perform static or dynamic loading according to the set parameters. The data acquisition module synchronously acquires the force signal of the load sensor 5 and the displacement signal of the displacement sensor 6 at a frequency of 1kHz and transmits them to the industrial control computer 10 in real time. The software dynamically plots the force-displacement cycle curve and displays the test progress and equipment status at the same time.

[0031] Test termination and data processing: When the piston ring reaches the set number of cycles or the displacement sensor 6 detects a sudden displacement change (such as 7mm), the system immediately issues a stop command, the linear actuator 2 stops loading, and the constant pressure servo hydraulic pump station is depressurized; the fully digital control software automatically calculates indicators such as fatigue life and maximum deformation, generates a test report, and stores the data in the industrial control computer 10, which supports exporting to Excel or PDF format for subsequent analysis.

[0032] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A fatigue testing machine for large-diameter piston rings, characterized in that, Includes test bench, constant pressure servo hydraulic pump station and electrical control system; The test bench is a double-column frame structure, including a double-column main frame (1), a linear actuator (2), a moving crossbeam (3), a workbench (4), a load sensor (5), and a displacement sensor (6). The constant pressure servo hydraulic pump station includes a base plate, an oil tank (7), an oil pump motor unit, a valve block (8), pipelines, a cooling system (71), a hydraulic system, and an oil source system. The hydraulic system adopts a differential circuit, and the oil source system is a pressure following system. The constant pressure servo hydraulic pump station is equipped with a force servo valve, a low-noise plunger pump, a precision oil filter, and an overflow valve. The electrical control system includes a computer console (9), an industrial control computer (10), fully digital control software, a data acquisition module and a servo controller. The industrial control computer (10) is connected to the data acquisition module, the servo controller and the constant pressure servo hydraulic pump station respectively. The test parameters are set, controlled in real time and processed in real time through the fully digital control software.

2. The large-diameter piston ring fatigue testing machine according to claim 1, characterized in that, The linear actuator (2) consists of an actuator body and a hydraulic control module. The hydraulic control module is connected to the valve block (8) of the constant pressure servo hydraulic pump station through a high-pressure pipeline. The output force range is 0-100kN and the dynamic response frequency is 0.1-15Hz.

3. The large-diameter piston ring fatigue testing machine according to claim 1, characterized in that, The lifting accuracy of the moving crossbeam (3) is ±0.1mm, and it is driven by a hydraulic cylinder and cooperated with a position sensor to achieve closed-loop control.

4. The large-diameter piston ring fatigue testing machine according to claim 1, characterized in that, The fully digital control software includes a parameter setting module, a real-time monitoring module, a data storage module, and a fault diagnosis module. The parameter setting module supports preset loading force, loading frequency, and number of cycles. The real-time monitoring module dynamically displays the force-displacement curve, test progress, and equipment status. The fault diagnosis module can alarm and automatically shut down the machine in case of sensor abnormalities or hydraulic system overpressure.

5. The large-diameter piston ring fatigue testing machine according to claim 1, characterized in that: The effective width between the columns of the double-column main frame (1) is not less than 530mm, and the height of the test space is not less than 1000mm. The moving crossbeam (3) is driven by a hydraulic cylinder to lift and lower, and is used to adjust the test space. The linear actuator (2) is installed on the moving crossbeam (3) and forms a loading force frame with the workbench (4). Its piston rod has a built-in displacement sensor (6). The load sensor (5) is installed on the upper end face of the workbench (4) and is used to detect the test load in real time.

6. The test method based on the large-diameter piston ring fatigue testing machine according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Preparation and inspection before use, check hydraulic oil, oil pipes, cables and power connections; Step 2: Install the sample, place the large-diameter piston ring on the test fixture of the workbench (4), adjust the moving beam (3) to align the piston rod of the linear actuator (2) with the piston ring surface, and clamp the piston ring. Step 3: Parameter setting. Input test parameters, including loading force, loading frequency, number of cycles, and test termination conditions, through the fully digital control software. Step 4: System startup and debugging. Start the constant pressure servo hydraulic pump station, preload and check sensor feedback to ensure the system is normal. Step 5: Start the test, start the test program, control the linear actuator (2) to perform static or dynamic loading, and the data acquisition module synchronously acquires force and displacement signals; Step 6: Test termination and data processing. When the termination conditions are met, the system will automatically stop, generate a test report, and store the data.

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