A test method for sealing ring oil seal performance

Abstract

The present invention discloses a sealing ring oil seal performance test method, which establishes an automatic test item set, configures test items, test sequence and corresponding test parameters according to the test requirements of the test piece, and provides combined test item configuration; by analyzing the change trend of the continuous pressure monitoring data of the sealing oil, it is judged whether there is leakage during the test process; if leakage occurs, an alarm is issued and the test is terminated; if there is no abnormality in the automatic monitoring, all test items are completed in sequence and the final test result is confirmed; through the tolerance test, a reasonable estimation of reliability parameters such as the minimum life, average life and maximum life of the product can be achieved, so that the product quality has a reliable quantitative basis.

Description

Technical Field

[0001] The invention belongs to the technical field of sealing performance testing of rubber products, and particularly relates to a sealing ring oil seal performance testing method. Background Art

[0002] As a high-precision component, sealing rings primarily prevent oil and gas leakage within a housing or pipeline, as well as the ingress of foreign matter such as air, water, and impurities. The seal's performance is closely linked to the proper functioning and lifespan of mechanical equipment. Therefore, conducting oil seal tests is a crucial task before sealing rings leave the factory or are assembled for use.

[0003] At present, there is still a lack of effective technical means to detect the performance of sealing rings. There are two commonly used methods: one is to use a universal friction and wear testing machine to conduct tribological tests on sealing materials, mainly to detect the friction coefficient, wear resistance and other tribological properties of the materials, which are far from the actual use of the sealing components. Therefore, this test method cannot reflect the anti-leakage ability of the sealing components under actual working conditions, nor can it judge the processing and assembly quality of the sealing components. If the sealing ring is applied to the actual working system based solely on the results obtained from this test, it is likely to cause serious adverse effects on the machinery and equipment; the other is to use a bench test to simulate the actual working conditions and measure the leakage of the sealing ring when it is working, but the leakage is only one of the comprehensive performance indicators of the sealing ring. Therefore, this experimental method cannot comprehensively evaluate the performance of the sealing ring.

[0004] Therefore, patent application CN102706551B, entitled "A Lip Seal Test Bench," addresses the development of a test bench for lip seals with a wide testing range, high accuracy, and comprehensive performance evaluation. The bench primarily consists of a support system, a power system, an oil circulation system, a torque measurement system, a leakage measurement system, a temperature measurement system, and a seal test system. During operation, an AC motor is connected to a frequency converter, which changes the frequency to achieve infinitely variable speeds between 0 and 6000 rpm. The oil inlet and outlet ports on the oil chamber are connected to the inlet and outlet ports of the oil pump, respectively, to provide circulating oil during the test. A small beaker is placed in the oil chamber to collect leaked oil, which is then weighed using a precision balance to determine the seal leakage. A static torque sensor is connected to a computer to display the friction torque during operation in real time. However, weighing methods are primarily suitable for larger leaks. For minor leaks, analysis currently relies on manual observation for oil seepage. This existing method is inefficient, particularly for testing the performance of lip seals of various specifications.

[0005] In summary, the existing sealing ring and oil seal performance test methods have problems such as poor adaptability, high reliance on manual on-site inspection and observation, difficulty in timely detecting leaks and terminating the test, and low test efficiency. Summary of the Invention

[0006] In response to the above problems, the present invention designs a sealing ring oil seal performance test method. Based on a general sealing ring oil seal performance test device, in particular, an oil seal performance test device for lip-type sealing rings of multiple specifications, the items and requirements of the oil seal performance tests of different types of lip-type sealing rings are summarized in common to form a unified configurable test procedure. For different sealing rings, it is only necessary to configure the parameters and test items according to the test requirements of the sealing ring, and the system can automatically complete the test work.

[0007] The present invention designs a sealing ring oil seal performance test method, which installs the test piece (also called test piece or test piece) into a sealing test device, and performs a sealing test by injecting sealing oil and setting the oil pressure according to the test requirements. The method is characterized in that an automatic test item set is established, and the test items, test sequence and corresponding test parameters are configured according to the test requirements of the test piece, and a combined test item configuration is provided; by analyzing the changing trend of the continuous pressure monitoring data of the sealing oil, it is judged whether there is a leakage during the test process; if a leakage occurs, such as a continuous downward trend in the pressure value, it can be suspected that a leakage has occurred, an alarm is issued and the test is terminated; after confirming that there is no oil leakage or other abnormalities, and it is only a false alarm caused by detection errors, the test can be continued; otherwise, the test is terminated and the problem is checked; if there is no abnormality in the automatic monitoring, all test items are completed in sequence, and the final test results are manually confirmed.

[0008] Furthermore, the test item set includes single tests and combination tests. The single tests include static tests, pressure tests, temperature tests, dynamic tests, radiation tests, etc. The single tests in the test item set generally refer to tests conducted by changing the conditions of the single test while other environmental conditions are normal working conditions. The combination test refers to a combination of at least two single tests; an oil seal performance test contains at least one combination test or two or more combination tests conducted at different times; the combination test is to combine two or more single tests with configured test parameters and conduct them synchronously or in sequence. When there is no leakage or other abnormality, the test is automatically completed according to the planned time until the result is confirmed after completion.

[0009] Furthermore, the pressure test includes a high-pressure test, a low-pressure test or a normal-pressure test. The normal pressure includes normal pressure (including atmospheric pressure) or daily working pressure (can also be average working pressure). The high pressure and low pressure are relative concepts. The high pressure mainly refers to the normal working pressure of the sealing ring, which refers to greater than or equal to the maximum working pressure, or 2 times or more of the normal pressure. The low pressure refers to less than or equal to the minimum working pressure; the temperature test includes a high-temperature test, a low-temperature test and a normal-temperature test. The specific temperature value is set according to the test needs. The normal temperature includes room temperature or daily working temperature. The high temperature refers to greater than or equal to the maximum working temperature, or 2 times or more of the normal temperature, and the low temperature refers to less than or equal to the minimum working temperature; the dynamic test includes a rotation test (the rotation speed can be set), a vibration test and a swing test. The frequency and amplitude of the vibration and swing during the test are set according to the test requirements; the rotation test includes a high-speed test and a normal-speed test. The normal speed includes the daily working speed. The high speed refers to greater than or equal to the maximum working speed, or 2 times or more of the normal speed.

[0010] Furthermore, the combination test includes static normal temperature and normal pressure test, static normal temperature and high pressure test, static normal temperature and low pressure test, static high temperature and normal pressure test, static high temperature and high pressure test, static high temperature and low pressure test, normal temperature and normal pressure and constant speed test, normal temperature and normal pressure and high speed test, normal temperature and normal pressure vibration test, normal temperature and normal pressure swing test, normal temperature and normal pressure radiation test, high temperature and high pressure and constant speed test, high temperature and high pressure and high speed test, high temperature and high pressure vibration test, high temperature and high pressure swing test, high temperature and high pressure radiation test, and combination test of the above tests in chronological order, etc. Any feasible single test combination can be carried out, and frequently used combination tests and their parameters can be preset in advance, which can effectively improve the efficiency of test item configuration.

[0011] Furthermore, the test item set also includes tolerance tests, which include general tolerance tests, life tests or extreme performance tests. The tolerance tests are sometimes also divided into static tolerance tests and dynamic tolerance tests. The tolerance test generally lasts no less than 24 hours, and the test environment is mainly in a relatively harsh environment; the general tolerance test includes 24 hours and normal temperature, normal pressure and normal speed tests, that is, continuous working performance tests under normal working conditions, and the test duration is generally selected as 24 hours, 48 ​​hours or 72 hours; the life test includes 24 hours and high temperature, high pressure and high speed tests, which verify whether the sampled products can reach the expected life through environmental conditions or time acceleration; the extreme performance test includes continuous high temperature, high pressure and high speed tests until the test piece leaks, and the time of leakage is recorded to facilitate subsequent life evaluation.

[0012] Furthermore, the tolerance test also includes product life estimation, and the product life estimation method includes natural index estimation method 1 or natural index estimation method 2 or common index method:

[0013] Let the normal working temperature be T0, the normal working pressure be P0, the normal working speed be V0, the tolerance test environment temperature be T1, the pressure be P1, the speed be V1, the product qualification rate η, the life adjustment coefficient α1, the index adjustment coefficient α2, and the test time be t1. The predicted life t of the natural index estimation method is:

[0014] t=α1ηexp(T1P1V1 / T0P0V0)

[0015] The second natural index estimation method predicts the life span t as:

[0016] t=α1ηexp(α2T1P1V1 / T0P0V0)

[0017] Let the density coefficient be k, and the commonly used exponential method to predict the life t is:

[0018] .

[0019] The above is a single test result, and the actual product life should generally be a statistical result; therefore, the same type of tolerance test should be carried out multiple times, generally not less than 5 times, and usually more than 10 times.

[0020] Furthermore, the analysis of the trend of changes in the continuous pressure monitoring data of the sealing oil includes filtering or fitting the continuous pressure monitoring data (generally linear fitting, both filtering and fitting use mature technologies), and a continuous decrease in the pressure value over time is judged as an oil leakage.

[0021] Furthermore, the method for judging whether the pressure value continuously decreases over time includes judging based on whether the filtering change rate or the slope of the straight-line fitting is (negative) less than a threshold value less than 0; wherein, for the filtering method, the threshold value can be considered to be 1 to 3 times the minimum resolution of the pressure gauge; for the straight-line fitting method, the threshold value can be taken as 1 to 10 times the minimum resolution of the pressure gauge divided by the continuous sampling time.

[0022] Furthermore, the test method steps include:

[0023] S1. Installation of the test piece: Install the test piece into the sealing test device;

[0024] S2. Set test items and sequence: Set one or more combined test items and their sequence according to the test requirements of the device under test;

[0025] S3. Set test parameters: Set test parameters according to test project requirements;

[0026] Steps S2 and S3 can be performed simultaneously.

[0027] S4. Oil filling: Inject the test oil into the test device to the preset test pressure, which is generally the pressure value of the first test;

[0028] S5. Start the test: perform the test operation and timing according to the preset test items and test parameters. This can be combined with step S4 for automatic execution.

[0029] S6. Oil leakage confirmation: During the test, after the test is terminated or completed, the oil leakage port shall be further inspected and confirmed.

[0030] Furthermore, the test method further includes: S7, pass rate analysis and / or life analysis, the pass rate analysis includes automatic pass rate analysis, and the life analysis can be performed by a life estimation method.

[0031] The advantages and beneficial effects of the present invention are as follows: a sealing ring oil seal performance test method designed by the present invention can timely detect leakage anomalies by setting a test item set and automatically monitoring and analyzing the oil pressure, without the need for manual timing or continuous monitoring and inspection. When there is no anomaly, the oil seal test is automatically performed in sequence, thereby effectively improving the efficiency of the sealing ring oil seal performance test; on the other hand, the pre-setting of the combination test also improves the efficiency of the test item configuration; furthermore, through the tolerance test, a reasonable estimation of reliability parameters such as the minimum life, average life, and maximum life of the product can be achieved, thereby providing a reliable quantitative basis for product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flowchart of the steps of the sealing ring and oil seal performance test method;

[0033] Figure 2 This is a structural diagram of a multi-specification lip seal oil seal performance test device;

[0034] Figure 3 yes Figure 2 Structural diagram of the sealed box of the test device.

[0035] Markings in the figure:

[0036] Hydraulic pump oil suction pipe 1, hydraulic pump oil inlet nozzle 2, hydraulic pump 3, hydraulic pump oil outlet nozzle 4, oil inlet pipe 5, sealing box oil inlet nozzle 6, sealing box 7, sealing box oil outlet nozzle 8, oil outlet pipe 9, control box 10, pressure regulating valve 11, oil barrel 12, platform 13;

[0037] Base 7.1, hydraulic cylinder 7.2, sealing cover 7.3, sealing ring 7.4, pressure gauge 7.5, oil seal seat 7.6, test box 7.7, cylinder 7.71, fixing seat 7.72, bearing 7.8, bracket 7.9, rotating shaft 7.10, drive motor 7.11, oil inlet hole 7.12, oil seal 7.13, test shaft 7.14, sealing gasket 7.15, oil outlet hole 7.16, oil leakage hole 7.17. DETAILED DESCRIPTION

[0038] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0039] Example 1

[0040] The present invention is to design a sealing ring oil seal performance test method, which installs the test piece (also called test piece or test piece) into the sealing test device, injects sealing oil and sets the oil pressure according to the test requirements to perform a sealing test. The method is characterized in that an automatic test item set is established, and the test items, test sequence and corresponding test parameters are configured according to the test requirements of the test piece, and a combined test item configuration is provided; by analyzing the trend of the continuous pressure monitoring data of the sealing oil, it is judged whether there is a leakage during the test process. If a leakage occurs, such as a continuous downward trend in the pressure value, it can be suspected that a leakage has occurred, an alarm is issued and the test is terminated to confirm that there is no oil leakage or other abnormalities. If the false alarm is merely caused by a detection error, the test can continue; otherwise, the test is terminated and the problem is investigated. If the automatic monitoring shows no abnormalities, all test items are completed sequentially, and the final test results are manually confirmed. The present invention eliminates the need for manual on-site observation of the oil leak port / hole (also known as an observation hole) at each node (such as manual confirmation of oil leakage after the static test is completed and before the dynamic test begins). If all goes well, the test can be continued as planned, thereby improving test efficiency and automation. The test device requires a high-sensitivity pressure gauge. In this embodiment, the HC-PC480 pressure gauge is selected. The pressure monitoring data is transmitted to the monitor in real time, and an audible and visual alarm service is provided.

[0041] Preferably, the test item set includes single tests and combination tests. The single tests include static tests, pressure tests, temperature tests, dynamic tests, radiation tests, etc. The single tests in the test item set generally refer to tests performed by changing the conditions of the single test under other environmental conditions as normal working conditions. The combination test refers to a combination of at least two single tests; an oil seal performance test includes at least one combination test or two or more combination tests conducted at different times; the combination test is to combine two or more single tests with configured test parameters and conduct them synchronously or in sequence. When there is no leakage or other abnormality, the test is automatically completed according to the planned time until the result is confirmed after completion.

[0042] Preferably, the pressure test includes a high-pressure test, a low-pressure test or a normal-pressure test. The normal pressure includes normal pressure (including atmospheric pressure) or daily working pressure. The high pressure and low pressure are relative concepts. The high pressure is mainly for the normal working pressure of the sealing ring, which refers to a pressure greater than or equal to the maximum working pressure, or 2 times or more of the normal pressure (generally 3 to 5 times can be selected), not the absolute value of the pressure. The low pressure refers to a pressure less than or equal to the minimum working pressure. Low pressure is rarely used, generally less than 0.5 times the normal pressure / daily working pressure. If the daily working pressure is small, it is sometimes directly referred to as low pressure. If the working pressure itself is a high pressure value, state, the high pressure of the present invention should be determined by the actual working environment requirements, generally not more than 2 times of the working high pressure or the maximum working pressure that may be encountered; the temperature test includes high temperature test, low temperature test, and normal temperature test, the normal temperature includes room temperature or daily working temperature, the high temperature refers to greater than or equal to the maximum working temperature, or 2 times or more of the normal temperature, the low temperature refers to less than or equal to the minimum working temperature, and the specific temperature value is set according to the test needs; the high temperature and low temperature are relative concepts, not absolute values, and are both relative to the daily room temperature or daily working temperature; the low temperature is rarely used, generally less than 0.5 times of the normal temperature / working temperature, if the working temperature When it is smaller, it is sometimes directly referred to as low temperature, or the lowest possible operating temperature; if the daily operating temperature is already high, the high temperature described in the present invention should be determined according to the actual working environment requirements, generally not exceeding twice the high working temperature or the maximum operating temperature that may be encountered; the dynamic test includes a rotation test (the rotation speed can be set), a vibration test, and a swing test. During the test, the frequency and amplitude of the vibration and swing are set according to the test requirements; the rotation test includes a high-speed test and a constant-speed test. The constant speed refers to the speed of the tested part in normal working condition, and the high speed is a relative concept. The high speed refers to a speed greater than or equal to the maximum working speed, or the constant speed 2 times or more, usually 3 to 5 times. When the normal speed itself is already a higher speed, the high speed is generally 2 times or the highest possible speed under the working state. The present invention uses static instead of low speed state; the radiation test refers to the electromagnetic radiation environment aging test, which is only carried out when the tested piece may have a relatively harsh long-term electromagnetic environment. This test is not required for general sealing test; the vibration test, swing test, and radiation test environmental parameters are set according to demand, generally based on the normal working environment or the possible worst environmental parameters, such as vibration frequency and amplitude, swing frequency and amplitude, radiation intensity, etc. during operation.

[0043] The setting of the test item set mainly depends on the test capability of the sealing test device and the maximum set of test environments that the test piece needs to be tested. The test item set of this embodiment includes all of the above test items (considering that general seals do not require low-pressure tests, vibration tests, swing tests, and low-temperature tests, the difference from Example x is that the test item set of this embodiment does not include radiation tests, does not include swing tests and vibration tests in dynamic tests, does not include low-pressure tests in pressure tests, and does not include low-temperature tests in temperature tests).

[0044] Preferably, the combination test includes a static normal temperature and pressure test, a static normal temperature and high pressure test, a static normal temperature and low pressure test, a static high temperature and normal pressure test, a static high temperature and high pressure test, a static high temperature and low pressure test, a normal temperature and normal pressure and constant speed test, a normal temperature and normal pressure and high speed test, a normal temperature and normal pressure vibration test, a normal temperature and normal pressure swing test, a normal temperature and normal pressure radiation test, a high temperature and high pressure and constant speed test, a high temperature and high pressure and high speed test, a high temperature and high pressure vibration test, a high temperature and high pressure swing test, a high temperature and high pressure radiation test, and a chronological combination test of the above tests, etc. Any feasible single test combination can be performed, and the program design and parameter configuration can be performed specifically according to the test requirements of the test piece; the chronological combination test may be performed first at a static normal temperature and normal pressure test, and then after it is normal, a static normal temperature and high pressure test is performed, and finally a high temperature and high pressure and high speed rotation test is performed. After the setting is completed, it is executed in the order of the program; presetting the frequently used combination tests and their parameters in advance can effectively improve the efficiency of the test item configuration.

[0045] Preferably, Figure 1 As shown, the test method steps include:

[0046] S1. Installation of the test piece: Install the test piece into the sealing test device;

[0047] The test device used in this embodiment is a multi-specification lip seal oil seal performance test device (this method is also applicable to single specification or other seal ring tests). Figure 2 、 3As shown, it includes a hydraulic pump oil suction pipe 1, a hydraulic pump oil inlet nozzle 2, a hydraulic pump 3, a hydraulic pump oil outlet nozzle 4, an oil inlet pipe 5, a sealing box oil inlet nozzle 6, a sealing box 7, a sealing box oil outlet nozzle 8, an oil outlet pipe 9, a control box 10, a pressure regulating valve 11, an oil barrel 12, and a platform 13; the platform includes a fixed platform, a vibrating platform or a rocking platform (such as a six-degree-of-freedom hydraulic turntable), the figure shows a fixed platform, which is used to install the sealing box, and the pressure pump and the control box can also be installed on it; if a temperature test is required, a heater or a temperature box is also required to be set up; if a radiation test is required, the entire test device can be placed in a radiation box or a radiation room, or the control box can be moved to the outside, which are not shown in the figure; the control box is electrically connected to the rotating motor of the sealing box, the hydraulic pump, the pressure regulating valve and / or the hydraulic cylinder 7.2 of the sealing box, the temperature box, the platform movement electronic control components, the radiation box, etc., which are also not shown in the figure. During the test, the test oil (aviation fuel) is injected into the test fixture through the oil suction pipe 1 and the hydraulic pump 3. After the oil is full, it enters the oil barrel 12 through the oil outlet pipe 9. The pressure environment in the sealed box is adjusted by the pressure regulating valve 11 to form a circulating test system.

[0048] The sealing box of this embodiment is a device for testing the performance of lip seals of various specifications. Figure 3As shown, it includes a bracket 7.9, a test box 7.7 is provided on one side of the bracket, the test box is composed of a cylinder 7.71 and a fixing seat 7.72, the fixing seat is connected to the side of the bracket by bolts, the cylinder is arranged horizontally, one end is connected to the fixing seat by bolts, the other end of the cylinder 7.71 is open, the test box 7.7 is provided with a rotating shaft 7.10 on the side close to the bracket 7.9, the rotating shaft and the test box are rotatably matched through a bearing 7.8, the end of the rotating shaft 7.10 close to the bracket 7.9 passes through the bracket 7.9, the bracket 7.9 and the fixing seat 7.72 are provided with corresponding through holes, the rotating shaft 7.10 passes through the bracket 7.9 and extends to the outside of the bracket, and a drive motor 7 is provided on one side of the bracket 7.9. .11, the end of the driving shaft of the driving motor 7.11 is a spline shaft, and the end of the rotating shaft 7.10 is provided with a corresponding spline hole for matching connection. The other end of the rotating shaft 7.10 is provided with a detachable test shaft 7.14, and the test shaft 7.14 is connected to the rotating shaft 7.10 by bolts. The diameter of the test shaft 7.14 can be changed according to the aperture of the oil seal 7.13 and then installed on the rotating shaft 7.10, so that the test shaft 7.14 can match oil seals 7.13 of different specifications. In order to make the test shaft 7.14 concentric with the rotating shaft 7.10 after matching, it can be positioned by a positioning pin, or the rotating shaft 7.10 can be designed into a step shape to form a positioning core shaft, and the test shaft 7.14 is provided with a positioning core hole to cooperate with the positioning core shaft for positioning. , a detachable oil seal seat 7.6 is provided in the test box 7.7 corresponding to the outer periphery of the test shaft 7.14, that is, a step hole for installing the oil seal seat 7.6 is provided in the cylinder 7.71 of the test box 7.7, and the oil seal seat 7.6 is installed in the step hole in the cylinder 7.71 by bolts. The outer periphery of the oil seal seat 7.6 is stepped, that is, it can be positioned with the cylinder 7.71 and is easy to install. The oil seal seat 7.6 has a stepped inner hole, which can be sleeved on the outer periphery of the test shaft 7.14 and can install the oil seal 7.13. The diameter of the oil seal seat 7.6 can be changed according to the outer diameter of the oil seal 7.13 and then installed on the test box 7.7, so that the oil seal seat 7.6 can match oil seals 7.13 of different specifications, and the oil seal seat 7.6 is close to the A sealing gasket 7.15 is provided at the joint between one side of the bracket 7.9 and the test box 7.14. The sealing gasket 7.15 is arranged on the end face of the stepped hole of the cylinder 7.71. The oil seal seat 7.6 is connected to the cylinder 7.71 by bolts and then presses the sealing gasket 7.15. An oil leakage hole 7.17 is provided at the bottom of the cylinder 7.71 between the oil seal 7.13 and the bearing 7.8. This arrangement makes it easy to observe whether the oil seal 7.13 leaks oil during the test. The upper end of the cylinder 7.71 on the side of the oil seal 7.13 away from the bearing 7.8 is provided with an oil inlet hole 7.12 (connected to the oil inlet nozzle 6 of the sealing box) and an oil outlet hole 7.16 (connected to the oil outlet nozzle 8 of the sealing box) is provided at the bottom. The test box 7.7 is away from the bracket 7.An axially detachable cover 7.3 is provided at one end of the cylinder 7.71. A hydraulic cylinder 7.2 is located on the side of the cover 7.3 facing away from the test chamber 7.6. The hydraulic cylinder 7.2 is mounted on the base 7.1, and its drive shaft is connected to the cover 7.3. Driven by the hydraulic cylinder 7.2, the cover 7.3 can close or open the opening of the cylinder 7.71. A sealing groove is provided at the end of the cylinder 7.71 corresponding to the cover 7.3, and a sealing ring 7.4 is located within the groove. A pressure gauge 7.5 is located on the end of the cylinder 7.71 closest to the cover 7.3.

[0049] In the above test device, a temperature sensor (thermometer) is installed on the outer shell of the sealing box 7, and a speed measuring motor is installed on the rotating shaft of the driving motor 7.11.

[0050] S2. Set test items and sequence: Set one or more combined test items and their sequence according to the test requirements of the device under test;

[0051] This embodiment takes the sealing performance test of a reinforced leather cup seal as an example. It is necessary to set up a static test 1 at normal temperature and pressure, a high-speed test at normal temperature and pressure, and a medium-speed test at normal temperature and pressure, and carry them out in sequence. Finally, a static test 2 at normal temperature and pressure is carried out, and a 24-hour static test is carried out (which can be regarded as a tolerance test).

[0052] S3. Set test parameters: Set test parameters according to test project requirements;

[0053] In this embodiment, the parameters of the static test 1 at normal temperature and pressure are set as follows: the temperature is room temperature, the oil pressure is increased to 0.3 MPa, and the test duration is 5 minutes;

[0054] Set the normal temperature and pressure high speed test parameters to 8072 rpm (rounded to 8100 rpm) and a test duration of 2 h. Other test conditions remain unchanged from the normal temperature and pressure static test 1.

[0055] Set the medium speed test parameters at normal temperature and pressure, taking 50% of the high speed, that is, 4036 rpm (rounded up to 4000 rpm), and the test duration for 30 minutes;

[0056] Set the parameters for the static test 2 at normal temperature and pressure to room temperature, maintain the oil pressure at 0.3 MPa, and last for 24 hours.

[0057] Steps S2 and S3 can be performed simultaneously.

[0058] S4. Oil filling: Inject the test oil into the test device to the preset test pressure, which is generally the pressure value of the first test;

[0059] In this embodiment, the sealing box cavity is filled with 4050 lubricating oil to 0.3 MPa. The oil can be directly injected according to the program through the control box until the first test pressure is reached. Alternatively, the oil can be injected first, and then the test items and parameters are set.

[0060] S5. Start the test: Execute the test operation and time the test according to the preset test items and test parameters. This can be combined with step S4 for automatic execution. The test operation includes automatically or manually adjusting the test parameters according to the test item parameter settings, such as adjusting the pressure to a set value. Automatic adjustment is generally based on feedback from detection sensors such as a force meter, thermometer, and motor tachometer.

[0061] S6. Oil leakage confirmation: During the test, after the test is terminated or after the test is completed, the oil leak port shall be further inspected and confirmed. The oil leakage confirmation during the test means that the continuous pressure monitoring shows that there is an oil leak, which requires manual confirmation. Generally, manual confirmation is required when the pressure drop is not obvious. If the pressure drop is obvious, no confirmation is required, and there must be an abnormality. The test termination means that other abnormalities occur in the test system or other reasons cause the test to be suspended or terminated.

[0062] Preferably, the test method includes the following steps: S7, yield analysis and / or life analysis (not shown in the figure). The yield analysis includes automatic yield analysis. The life analysis can be performed using life estimation methods, including empirical estimation methods or quantitative calculation methods. The automatic yield analysis requires the design of a yield statistical model (or module). When configuring the test item items, a yield analysis flag is set so that the automatic test system can identify the test as a yield statistical test and record the test results in the pass / fail flag. Finally, the yield is automatically calculated based on the end mark of a certain round of yield testing.

[0063] The pass rate analysis method is relatively common. This embodiment can test the pass rate η of batch products through static normal temperature and pressure tests, normal temperature, normal pressure and constant speed tests, short-time high temperature, high pressure and high speed tests or combined tests. The specific test parameters and procedures can be set according to product testing standards or user needs; for the sealing ring and oil seal performance test, when the product pass rate needs to be tested, generally for the same batch of products, when the test items and parameters are set, the test time of a single product should not be too long, and the principle is that the test of one product can be completed in no more than 2 hours. The specific test should be determined according to the situation; the number of products tested for the pass rate test should be no less than 10, and usually should be more than 20. The ratio of the number of qualified products to the total number of tested products is used as the test result.

[0064] Example 2

[0065] The difference from Example 1 is that the test item set also includes a tolerance test, which includes a general tolerance test, a life test, or an extreme performance test. The tolerance test is sometimes divided into a static tolerance test and a dynamic tolerance test. The tolerance test generally lasts for no less than 24 hours, and the test environment is mainly a relatively harsh environment, such as a high-speed rotation tolerance test under maximum working pressure, maximum working temperature, and worst radiation environment, or a high-speed rotation tolerance test under a test environment with twice or more of the above environmental parameters. The tolerance test is essentially a combination test, and because of the special nature of its test purpose, it is generally listed separately in engineering projects;

[0066] The general tolerance test includes 24 hours and normal temperature, pressure and speed tests, that is, continuous working performance tests under normal working conditions. The test duration is generally selected to be 24 hours, 48 ​​hours or 72 hours. If there are no abnormalities after the test, the test piece is still a qualified product and can be used normally. After the test of tolerance to harsh working environment is completed, the test piece is scrapped and can no longer be used normally.

[0067] The life test includes 24 hours and high temperature, high pressure and high speed tests. Through environmental conditions or time acceleration, it is verified whether the sampled products can reach the expected life. Other accelerated environments such as vibration and electromagnetic are added according to the test requirements. If leakage occurs during the test, the time of leakage must be recorded to facilitate subsequent life assessment. After the test is completed, the test piece is scrapped and no longer in normal use.

[0068] The extreme performance test includes continuous high temperature, high pressure and high speed testing until the test piece leaks, and the time of leakage is recorded to facilitate subsequent life assessment; after the test is completed, the test piece is scrapped and no longer in normal use;

[0069] The tolerance test also sets extreme environments and time limits, such as the maximum test temperature not exceeding 2 / 3 of the melting point of the test piece, the maximum pressure not exceeding 5 times the working pressure, the maximum speed not exceeding 5 times the working speed (or the maximum speed of the test device), and the time not exceeding 240 hours.

[0070] Preferably, the tolerance test further includes product life estimation, and the product life estimation method (quantitative calculation method) includes natural index estimation method 1 or natural index estimation method 2 or common index method:

[0071] Let the normal working temperature be T0, the normal working pressure be P0, the normal working speed be V0, the tolerance test environment temperature be T1, the pressure be P1, the speed be V1, the product qualification rate η, the life adjustment coefficient α1, the index adjustment coefficient α2, and the test time be t1. The predicted life t of the natural index estimation method is:

[0072] t=α1ηexp(T1P1V1 / T0P0V0)

[0073] The second natural index estimation method predicts the life span t as:

[0074] t=α1ηexp(α2T1P1V1 / T0P0V0)

[0075] Let the density coefficient be k, and the commonly used exponential method to predict the life t is:

[0076] .

[0077] The above is a single test result, and the actual product life should generally be a statistical result; therefore, the same type of tolerance test should be carried out multiple times, generally not less than 5 times, and usually more than 10 times.

[0078] Note that if a value of 0 appears in T0, P0, or V0, it should generally be avoided by unit conversion; or, if the actual measured values ​​of the tolerance test environment temperature T1, pressure P1, and speed V1 are much greater than 1, then if a value of 0 appears in T0, P0, or V0, the value 0 can be replaced by the value 1 for estimation.

[0079] The above natural index estimation method 1 and natural index estimation method 2 focus on the natural power exponential relationship between the life of the accelerated test and the change of test parameters, as well as the influencing factors of the actual product qualification rate η. At the same time, considering the non-strict natural exponential relationship, the life adjustment coefficient α1 and the exponential adjustment coefficient α2 are used for adjustment; when there are no empirical parameters, the values ​​of α1 and α2 can be 1; when there are empirical parameters, the empirical parameter values ​​can be used; for the natural index estimation method 1, the method for obtaining the empirical parameter value of α1 can adopt the ratio of the statistical mean of the actual service life of multiple (more than 10) products of the same batch to the statistical mean of the life estimation values ​​of multiple (more than 10) products of the same batch in the extreme performance test. If the ratio results of different batches of products can be obtained, they can be averaged again and used as the empirical parameter; for the natural index estimation method 2, the method for obtaining the empirical parameters of α1 and α2 is still the same as above, using the statistical mean of the actual service life of products of the same batch as the life result, and then fitting the empirical values ​​of α1 and α2 through least squares optimization or other mathematical optimization methods.

[0080] The difference between the conventional exponential method and the natural exponential method is that the base number is no longer known. It also requires an optimal fit based on actual product lifespan statistics. Only after obtaining empirical values ​​can a proper lifespan estimation be performed. In short, both estimation methods are based on the exponential relationship between the multiples of the accelerated test parameter changes. This example uses the natural exponential estimation method 1 for lifespan estimation.

[0081] For general tolerance tests, the lifespan obtained by the above-mentioned natural index estimation method is generally called the minimum lifespan; the estimated lifespan obtained from life tests is generally called the normal lifespan of the product; the estimated lifespan obtained from extreme performance tests is generally called the maximum lifespan of the product. When no leakage occurs during the extreme test (when the time is automatically terminated), the maximum lifespan can also be considered to be no less than the estimated value.

[0082] Example 3

[0083] The difference from Example 1 is that a trend analysis of continuous pressure monitoring data is carried out, including filtering or fitting the continuous pressure monitoring data of the sealing oil (generally linear fitting, both filtering and fitting use mature technologies, such as Kalman filtering and least squares fitting. This embodiment uses least squares linear fitting because, in theory, when no leakage occurs, the continuous pressure monitoring value should be a horizontal straight line with a slope of 0). If the pressure value decreases continuously over time, it is judged that there is an oil leakage. Generally, at least 10 frames of monitoring data should be processed continuously. If the monitoring data is one frame per second, it should be monitored continuously for at least 10 seconds. The filtering A Kalman filtering method based on a constant velocity model can be used, and when the filtering rate is negative, it is determined that an oil leak has occurred; the linear fitting method based on least squares can be used, and when the slope of the line is negative, it is determined that an oil leak has occurred; this embodiment recommends the use of a linear fitting method, which is simple and, for this application, has a higher credibility as the continuous sampling time of a single test is extended, because even if there is a detection or calculation error, the error impact will become smaller and smaller as time goes by, and the probability of influence of all measured values ​​is the same, while the effect of the filtering method is not obvious, and the probability of influence of the current measured value is greater.

[0084] Preferably, the method for determining whether the pressure value continuously decreases over time includes determining whether the filtered change rate or the linear fitting slope (is negative) is less than a threshold value less than 0. Due to the particularity of the test in this test device, after the sealing oil pressure in the test device is fixed, the valve and pump are closed, and the test is carried out without adding pressure. Theoretically, when there is no leakage, the gauge pressure value should be constant, that is, whether the change rate is calculated by filtering or the slope is calculated by linear fitting, the theoretical value should be 0. However, considering the random errors in monitoring data and computer calculation errors, it is difficult to achieve an absolute zero value. Therefore, in engineering practice, it is generally not simply determined as less than 0, but rather as less than a threshold value less than 0. The selection of the threshold value is related to the method used and the number of sampling frames (duration). Among them, for the filtering method, the threshold value can be considered to be 1 to 3 times the minimum resolution of the pressure gauge. For example, if the minimum resolution of the pressure gauge is 0.001 kPa, the threshold value can be -0.002 kPa / s. For the linear fitting method, the threshold value can be 1 to 10 times the minimum resolution of the pressure gauge divided by the continuous sampling duration. For example, if the continuous sampling is 10 seconds, the threshold value can be -0.0005 kPa / s.

[0085] It should be noted that even if the pressure gauge indicates an oil leak, this does not necessarily mean the seal is leaking. Therefore, the test should be stopped and the leak hole should be further observed to confirm the leak. If the seal is indeed leaking, the tested part is unqualified. If there are no signs of oil leakage at the leak hole, it is likely that another part of the test device is leaking and requires repair and retesting. Under normal circumstances, the leaking device itself has been inspected multiple times. Therefore, in most cases, the oil leak detected by the pressure gauge is inevitably a leak in the tested seal.

[0086] Example 4

[0087] The difference between this embodiment and embodiment 1 is that the sealing performance of another reinforced leather cup assembly is tested to further demonstrate the test items and parameter configuration. The test items of this embodiment include a normal temperature high-pressure swing test, a normal temperature low-pressure swing test, and a 24-hour static normal temperature and pressure test.

[0088] In this embodiment, the cavity is filled with 21260 II oil until the oil is discharged from the exhaust hole, and the oil filling pressure is not greater than 0.1 MPa (the actual oil pressure is 0.13 MPa);

[0089] Set the parameters for the normal temperature high-pressure swing test to 0.1 MPa and maintain the pressure for 5 minutes. During the pressure holding process, make the cavity and the shaft swing relative to each other 60 times with a swing amplitude of ±15°. Observe and record any oil leakage.

[0090] Set the parameters for the normal temperature and low pressure swing test, reduce the pressure to 0.02 MPa, and maintain the pressure for 5 minutes. During the pressure holding process, make the cavity and the shaft swing relative to each other 60 times with a swing amplitude of ±15°. Observe and record any oil leakage.

[0091] Set up a 24-hour static normal temperature and pressure test with a pressure of 0.02MPa. Park for 24 hours and observe whether there is any oil leakage and record it.

[0092] The basic principle of the present invention is: by setting a test item set, convenient configuration of test items during actual testing can be achieved, and the preset combination test items can effectively improve the configuration efficiency of test items and test parameters; through automatic oil pressure monitoring and analysis, no manual timing or continuous monitoring and inspection is required, and leakage abnormalities can be discovered in time. When there is no abnormality, the oil seal test is automatically carried out in sequence, so that the test of the vast majority of qualified products can be carried out continuously, thereby effectively improving the efficiency of the sealing ring oil seal performance test; by establishing a pass rate statistical model, especially for products of the same batch, information such as the number of tests and the number of qualified products is recorded and counted, which facilitates subsequent analysis of product quality; furthermore, through tolerance testing and establishing a life estimation method, reasonable estimation of reliability parameters such as the minimum life, average life, and maximum life of the product can be achieved, so that the product quality has a credible quantitative basis.

[0093] The above is only a partial and more comprehensive embodiment of a sealing ring oil seal performance test method of the present invention. In fact, different single tests and combination tests can be set according to different types of sealing rings and different functions of the test equipment. Different combination tests can also be designed into a test item set for direct call. There are many preferred combination embodiments, and these combinations should also be regarded as the protection scope of the present invention, and they will not be listed here one by one.

Claims

1. A sealing ring oil seal performance test method, which is characterized by: installing the test piece into a sealing test device, injecting sealing oil and setting the oil pressure according to the test requirements to perform a sealing test, Establish an automatic test project set, configure test items, test sequence, and corresponding test parameters according to the test requirements of the test piece, and provide combined test project configuration; through the analysis of the trend of the continuous pressure monitoring data of the sealing oil, determine whether there is leakage during the test. If leakage occurs, an alarm will be issued and the test will be terminated; if there is no abnormality in the automatic monitoring, all test items will be completed in sequence and the final test results will be confirmed; The test item set also includes tolerance test, which includes general tolerance test, life test or extreme performance test; The general tolerance test includes a 24-hour test at normal temperature, pressure and speed; the life test includes a 24-hour test at high temperature, high pressure and high speed; the extreme performance test includes a continuous high temperature, high pressure and high speed test until the test piece leaks; The tolerance test also includes product life estimation, and the product life estimation method includes natural index estimation method 1 or natural index estimation method 2 or common index method: Let the normal working temperature be T0, the normal working pressure be P0, the normal working speed be V0, the tolerance test environment temperature be T1, the pressure be P1, the speed be V1, the product qualification rate η, the life adjustment coefficient α1, the index adjustment coefficient α2, and the test time be t1. The predicted life t of the natural index estimation method is: t=α1ηexp(T1P1V1 / T0P0V0) The second natural index estimation method predicts the life span t as: t=α1ηexp(α2T1P1V1 / T0P0V0) Let the density coefficient be k, and the commonly used exponential method to predict the life t is: 。 2. A sealing ring oil seal performance test method according to claim 1, characterized in that: The test item set includes single tests and combination tests. The single tests include static tests, pressure tests, temperature tests, dynamic tests, and radiation tests. The combination test refers to a combination of at least two single tests. An oil seal performance test includes at least one combination test or two or more combination tests conducted at different times.

3. A sealing ring oil seal performance test method according to claim 2, characterized in that: The pressure test includes a high-pressure test, a low-pressure test or a normal-pressure test. The normal pressure includes normal pressure or daily working pressure. The high pressure refers to a pressure greater than or equal to the maximum working pressure, or 2 times or more of the normal pressure. The low pressure refers to a pressure less than or equal to the minimum working pressure. The temperature test includes a high-temperature test, a low-temperature test and a normal-temperature test. The normal temperature includes room temperature or daily working temperature. The high temperature refers to a pressure greater than or equal to the maximum working temperature, or 2 times or more of the normal temperature. The low temperature refers to a pressure less than or equal to the minimum working temperature. The dynamic test includes a rotation test, a vibration test and a swing test. The frequency and amplitude of vibration and swing during the test are set according to the test requirements. The rotation test includes a high-speed test and a normal-speed test. The normal speed includes the daily working speed. The high speed refers to a pressure greater than or equal to the maximum working speed, or 2 times or more of the normal speed.

4. A sealing ring oil seal performance test method according to claim 3, characterized in that: The combination test includes static normal temperature and normal pressure test, static normal temperature and high pressure test, static normal temperature and low pressure test, static high temperature and normal pressure test, static high temperature and high pressure test, static high temperature and low pressure test, normal temperature and normal pressure and constant speed test, normal temperature and normal pressure and high speed test, normal temperature and normal pressure vibration test, normal temperature and normal pressure swing test, normal temperature and normal pressure radiation test, high temperature and high pressure and constant speed test, high temperature and high pressure and high speed test, high temperature and high pressure vibration test, high temperature and high pressure swing test, high temperature and high pressure radiation test, and combination tests of the above tests in chronological order.

5. A sealing ring oil seal performance test method according to any one of claims 1 to 4, characterized in that: The analysis of the changing trend of the continuous pressure monitoring data of the sealing oil includes filtering or fitting the continuous pressure monitoring data, and a continuous decrease in the pressure value over time is judged as an oil leakage.

6. A sealing ring oil seal performance test method according to claim 5, characterized in that: The method for judging whether the pressure value continuously decreases over time includes judging based on whether the filtering change rate or the straight-line fitting slope is less than a threshold value less than 0, wherein the filtering method threshold value is 1 to 3 times the minimum resolution of the pressure gauge; the straight-line fitting method threshold value is 1 to 10 times the minimum resolution of the pressure gauge divided by the continuous sampling time.

7. A sealing ring oil seal performance test method according to any one of claims 1 to 4, characterized in that: The test method steps include: S1. Installation of the test piece: Install the test piece into the sealing test device; S2. Set test items and sequence: Set one or more combined test items and their sequence according to the test requirements of the device under test; S3. Set test parameters: Set test parameters according to test project requirements; S4. Oil filling: inject the test oil into the test device to the preset test pressure; S5. Start the test: execute the test operation and start the timing according to the preset test items and test parameters; S6. Oil leakage confirmation: During the test, after the test is terminated or completed, the oil leakage port shall be further inspected and confirmed.

8. A sealing ring oil seal performance test method according to claim 7, characterized in that: The test method further includes: S7, pass rate analysis and / or life analysis, wherein the pass rate analysis includes automatic pass rate analysis.

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