A reciprocating seal test apparatus and verification method for aircraft hydraulic actuators

Abstract

This invention discloses a reciprocating sealing test device and verification method for aviation hydraulic actuators, belonging to the field of airborne equipment testing and verification. It includes end caps, nuts, outer cylinders, hexagonal socket screws, pipe fittings, limit blocks, partition baffles, piston rods, and bushings, etc., which are assembled to form a complete component-level sealing test device. The device involves pre- and post-test inspections of the seals to be tested, as well as inspection of the quality of the moving surfaces of the test device. The seals are then assembled into the test device, and their installation process adaptability is checked. The test device is installed on a test bench, and sealing characteristic tests are conducted, including break-in tests, ambient temperature, high temperature, and low temperature performance tests, low-pressure static tests, and high-pressure static tests. Environmental adaptability tests are also conducted, including low-temperature storage, low-temperature operation, high-temperature storage, high-temperature operation, and temperature shock. Finally, a seal life durability test is performed, including ambient temperature, high temperature, and low temperature motion durability tests. After the tests, a disassembly inspection is conducted.

Description

Technical Field

[0001] This invention belongs to the field of component-level verification testing technology, and in particular relates to a reciprocating sealing test device and verification method for aviation hydraulic actuators. Background Technology

[0002] The trend towards higher pressure and higher power in aircraft hydraulic systems is well-known. Currently, the mature hydraulic system pressure in China is 21 MPa. Although the technical standard system for 28 MPa pressure systems is still under development, domestic hydraulic systems already use 28 MPa pressure. Tracing the development of aircraft hydraulic systems abroad, foreign suppliers have successfully implemented 35 MPa pressure in civil aircraft such as the B787 and A380. Through investigation, statistics, and analysis of the current sealing status of electromechanical products in my country, leakage problems exist to some extent in both dynamic and static seals.

[0003] Combined seal performance testing primarily assesses the sealing performance of combined seals under multi-factor coupling conditions, explores evaluation criteria for combined seal performance, provides data support and verification for the response laws and failure models of force-heat-fluid multi-field coupling factors, and provides verification and guidance for the optimization and control of combined seals. However, there is a lack of design methods and means for optimizing and comprehensively controlling seal performance, particularly regarding seal failure risk, durability, and reliability improvement. Effective and rapid verification methods are also lacking, resulting in long verification cycles, high costs, and questionable reliability of solutions. While static and conventional condition tests typically meet the requirements, many problems arise during equipment use under actual operating conditions, such as leakage, uneven wear, and piston rod damage. Summary of the Invention

[0004] The purpose of this invention:

[0005] Based on the verification standards for combined seals of aviation hydraulic actuators, this invention provides a reciprocating seal test device and verification method for hydraulic actuators, enabling the verification of linear reciprocating tests on combined seals of hydraulic actuators and promoting the improvement of the quality of seals for aviation hydraulic actuators.

[0006] Technical solution:

[0007] A reciprocating sealing test device for an aviation hydraulic actuator includes an outer cylinder 3, a piston rod 8 and a bushing 9. The outer cylinder 3 has an oil inlet and an oil outlet. The bushing 9 is coaxially arranged inside the outer cylinder 3. The bushing 9 is provided with a bushing oil passage 20. The bushing oil passage 20 corresponds to the oil inlet and oil outlet of the outer cylinder 3.

[0008] The bushing 9 has two inner static sealing grooves 11 on its outer circumference, and the two inner static sealing grooves are symmetrically arranged on both sides of the bushing oil inlet 20. The inner static sealing grooves 11 are provided with O-rings and retaining rings. The outer circular surfaces at both ends of the bushing 9 have outer static sealing grooves 12, and the outer static sealing grooves 12 are provided with O-rings and retaining rings.

[0009] The piston rod 8 is slidably disposed within the bushing 9. Piston rod combination sealing grooves 15 are provided on the outer circular surfaces at both ends of the piston rod 8. From the inside to the outside, the piston rod 8 is sequentially fitted with a partition baffle 7 and an end cap 1. The end face of the partition baffle 7 near the piston rod combination sealing groove 15 forms a piston rod support ring groove 16 between it and the piston rod 8. The piston rod combination sealing groove 15 is provided with a combination seal, and the piston rod support ring groove 16 is provided with a support ring.

[0010] The inner circular surface of the partition baffle 7 is provided with a static sealing groove 18, and the outer circular surface is provided with a combined sealing groove 17. The combined sealing groove 17 is provided with a combined sealing element, and the static sealing groove 18 is provided with an O-ring and a retaining ring.

[0011] The inner circular surface of the end cap 1 is provided with an end cap static sealing groove 14, and the outer circular surface is provided with an end cap dust scraper groove 13. The end cap static sealing groove 14 is provided with an O-ring and a retaining ring, and the dust scraper groove 13 is provided with a dust scraper ring.

[0012] Furthermore, the partition baffle 7 and the end cap 1 are locked to the outer circular surfaces at both ends of the piston rod 8 by nuts 2.

[0013] Furthermore, the oil inlet of the outer cylinder 3 is fitted with an oil inlet pipe connector 10 via an internal hexagon screw 4, and the oil outlet of the outer cylinder 3 is fitted with an oil outlet pipe connector 5 via an internal hexagon screw 4; a pipe connector static sealing groove 19 is provided on the outer circular surface of the oil inlet pipe connector 10 that contacts the inner wall of the oil inlet of the outer cylinder 3, and a pipe connector static sealing groove 19 is provided on the outer circular surface of the oil outlet pipe connector 5 that contacts the inner wall of the oil outlet of the outer cylinder 3; the pipe connector static sealing groove 19 is provided with an O-ring and a retaining ring.

[0014] Furthermore, limiting blocks 6 are provided on both sides of the outer cylinder 3 to limit the bushing 9.

[0015] Furthermore, the outer cylinder 3 is provided with oil leakage ports 21 at both ends, and the oil leakage ports 21 are located between the inner end face of the limiting block 6 and the outer end face of the bushing 9.

[0016] 6. A verification method for a reciprocating seal test device for an aircraft hydraulic actuator, comprising sealing characteristic test, environmental adaptability test and reciprocating life test of the combined seal.

[0017] Furthermore, the sealing performance test of the combined seal includes the following steps:

[0018] Step 11: Confirm the test conditions according to the hydraulic actuator product specifications, including the high temperature T. 高 Low temperature T 低 and high voltage P 高 Low-pressure P 低 ;

[0019] Step 12: Install the sealing test device on the test bench, start the program, and the piston rod 8 will reciprocate within the bushing 9 at least 500 times to complete the break-in test of the combined seal to be verified, and then end the program.

[0020] Step 13: Restart the program and introduce room temperature oil (15-35°C) into the sealed oil chamber between the bushing 9 and the piston rod 8 through the inlet pipe joint 10. Close the outlet pipe joint 5 and conduct a 3-minute pressure test. Record the leakage situation.

[0021] Step 14: Set the reciprocating stroke and frequency according to the actual working conditions, so that the combined seal to be verified is under high pressure P. 高 and low pressure P 低 The lower piston rod reciprocated 200 times each, and the test data was recorded to complete the room temperature performance test;

[0022] Step 15: Place the test apparatus in the temperature control chamber and adjust the temperature of the chamber to T at a rate of 3℃ / min. 高 After the temperature inside the temperature control chamber stabilizes, maintain this temperature for a period of time, and wait for the combined seals and oil to reach T. 高 And stabilize, conduct a 3-minute pressure holding test under high pressure, and record the leakage situation;

[0023] Step 16: Based on the actual working conditions, in P 高 and P 低 The lower piston rod 8 reciprocates 200 times each, and the leakage test data is recorded to complete the high-temperature performance test;

[0024] Step 17: Place the test apparatus in the temperature control chamber and adjust the temperature of the chamber to T at a rate of 3℃ / min. 低 After the temperature inside the temperature control chamber stabilizes, maintain this temperature for a period of time, and wait for the combined seals and oil to reach temperature T. 低 And stabilize, conduct a 3-minute pressure holding test under high pressure, and record the leakage situation;

[0025] Step 18: Based on the actual working conditions, in P 高 and P 低 The lower piston rod 8 reciprocates 200 times each, and the leakage test data is recorded to complete the low temperature performance test;

[0026] Step 19: Install the test device on the low-pressure static sealing test bench, connect the oil inlet pipe to 10 and introduce oil at a pressure of 0.02MPa and maintain it for 3 minutes. Record the leakage situation to complete the low-pressure static sealing test. Install the test device on the high-pressure static sealing test bench, and provide oil pressures of 50%, 100%, and 150% of the actuator's rated working pressure respectively, maintain each pressure for 3 minutes, and record the leakage situation.

[0027] Furthermore, the environmental adaptability test of the combined seal is as follows: five environmental adaptability tests are conducted, namely low temperature storage, low temperature operation, high temperature storage, high temperature operation, and temperature shock. The test procedures are carried out in accordance with GJB150A-2009 Military Equipment Laboratory Environmental Test Method. All environmental adaptability tests are conducted by installing the combined seal on the test device.

[0028] Among them, low temperature storage, high temperature storage and temperature shock tests require the test device to be naturally filled with working medium without the application of additional hydraulic pressure; low temperature operation and high temperature operation tests require the test device to be filled with working medium at the rated operating pressure.

[0029] Before and after each environmental adaptability test, the combined seals are subjected to a room temperature performance test.

[0030] Furthermore, the cyclic life test of the combined seal includes the following steps:

[0031] Step 21: Determine the normal temperature and high temperature T based on the proportion of each operating condition throughout the entire life cycle of the hydraulic product using the combined seal. 高 Low temperature T 低 The number of reciprocating motion cycles in the reciprocating motion durability test is used to conduct a multi-stage life test, and N is defined as... 常 Number of reciprocating motions at room temperature, N 高 For the number of reciprocating motions at high temperature, N 低 This represents the number of reciprocating motions at low temperatures.

[0032] Step 22: Install the test apparatus on the test bench, start the program, set the stroke and frequency of the electric cylinder on the test bench according to the actual working conditions, start the electric cylinder, and the combined seal to be verified is at P 高 and P 低 The following reciprocating work N 常 / 2 times, record the leakage situation at the end of the test, and complete the room temperature reciprocating motion durability test;

[0033] Step 23: Place the test apparatus in the temperature control chamber and adjust the temperature of the chamber to T at a rate not exceeding 3℃ / min. 高 After the temperature inside the temperature control chamber stabilizes, wait for the combined seals and oil to reach T. 高 And stabilize, set the electric cylinder stroke and frequency according to the actual working conditions, start the electric cylinder, and combine the seals under high pressure P高 and P 低 The following reciprocating work N 高 / 2 times, record the leakage situation at the end of the test, and complete the high temperature reciprocating motion durability test;

[0034] Step 24: Place the test apparatus in the temperature control chamber and adjust the temperature of the chamber to T at a rate not exceeding 3℃ / min. 低 After the temperature inside the temperature control chamber stabilizes, wait for the combined seals and oil to reach T. 低 And stabilize, set the electric cylinder stroke and frequency according to the actual working conditions, start the electric cylinder, and combine the seals under high pressure P 高 and P 低 The following reciprocating work N 高 / 2 times, record the leakage situation at the end of the test, and complete the low temperature reciprocating motion durability test.

[0035] Furthermore, the assembled seals that have completed sealing characteristic tests, environmental adaptability tests, and cyclic life tests are disassembled for inspection, photographed for evidence, and recorded.

[0036] Beneficial effects

[0037] This invention proposes a test device for verifying the combined seals of aviation hydraulic actuators, including end caps, nuts, outer cylinders, hexagonal socket screws, pipe fittings, limit blocks, partition baffles, piston rods, and bushings. These components are assembled to form a complete component-level sealing test device. First, the seals to be tested undergo pre- and post-test inspections, including visual and dimensional checks, and quality checks of the moving surfaces of the test device. Then, the seals are assembled into the test device, and their suitability for the installation process is checked. The test device is then installed on a test bench, and sealing characteristic tests are conducted, including break-in tests, room temperature, high temperature, and low temperature performance tests, low-pressure static tests, and high-pressure static tests. Next, environmental adaptability tests are performed, including low-temperature storage, low-temperature operation, high-temperature storage, high-temperature operation, and temperature shock. Following this, a seal life durability test is completed, including room temperature, high temperature, and low temperature motion durability tests. Finally, a disassembly inspection is performed after the tests. This invention addresses the modern aviation field's need for component-level testing and verification of high-quality hydraulic actuator seals. The device's structure and verification methods exhibit high integration and specialization, and have promising prospects for practical engineering applications. Attached Figure Description

[0038] Figure 1 Schematic diagram of the experimental apparatus of this invention;

[0039] Figure 2 This is a schematic diagram of the appearance of the experimental device of the present invention;

[0040] Figure 3 This is the experimental method flow of the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and specific examples: Figure 1-2 As shown, this invention proposes a reciprocating sealing test device for an aviation hydraulic actuator. The component-level verification device includes an end cap 1, a nut 2, an outer cylinder 3, an internal hexagon screw 4, an oil outlet pipe joint 5, a limiting block 6, a partition baffle 7, a piston rod 8, a bushing 9, an oil inlet pipe joint 10, a static sealing groove inside the bushing 11, a static sealing groove outside the bushing 12, a dust scraper groove on the end cap 13, a static sealing groove on the end cap 14, a combined sealing groove on the piston rod 15, a groove on the piston rod support ring 16, a combined sealing groove on the partition baffle 17, a static sealing groove on the partition baffle 18, a static sealing groove on the pipe joint 19, an oil inlet on the bushing 20, and a leakage port 21, etc.

[0043] In this embodiment, leakage ports 21 are provided on both sides of the lower part of the outer cylinder for collecting leakage medium.

[0044] In this embodiment, the bushing is provided with a bushing oil inlet 20 in the middle. O-rings and retaining rings are installed in the inner static sealing groove 11 and the outer static sealing groove 12 of the bushing. The bushing with the sealing ring installed is inserted from the center of the outer cylinder. Between the bushing and the outer cylinder, a sealing oil cavity is formed by the inner static sealing groove 11 of the bushing.

[0045] In this embodiment, a combined seal is installed in the piston rod combined sealing groove 15, and a support ring is installed in the piston rod support ring groove 16.

[0046] In this embodiment, a combined seal is installed in the partition baffle combined sealing groove 17, and an O-ring and a retaining ring are installed in the partition baffle static sealing groove 18. The partition baffle 7 with the seal installed is then inserted from both ends of the piston rod 8. The flat end face of the partition baffle 7 is tightly fitted with the piston head end face of the piston rod 8, so that the support ring groove forms a complete groove.

[0047] In this embodiment, a dust scraper ring is installed in the dust scraper groove 13 of the end cover, and an O-ring and a retaining ring are installed in the static sealing groove 14 of the end cover. The end cover 1 with the sealing elements installed is then inserted from both ends of the piston rod 8. The flat end face of the end cover 1 is tightly fitted with the flat end face of the partition baffle 7, so that the dust scraper groove forms a complete groove.

[0048] In this embodiment, the nut 2 is installed on both sides of the piston rod 8 through the threads at both ends of the piston rod 8. The nut 2 is tightened so that the end faces of the piston rod 8, the partition baffle 7 and the end cover 1 fit tightly together, thus completing the assembly of the piston rod 8.

[0049] In this embodiment, the fully assembled piston rod 8 is inserted through the center of the bushing 9, and a sealing oil cavity is formed between the area between the piston rod assembly sealing groove 15 and the bushing.

[0050] In this embodiment, the limiting block 6 is installed to the outer cylinder 3 through the threads on both sides of the outer cylinder 3, and the limiting block 6 is tightened so that the inner end face of the limiting block 6 is tightly fitted with the two end faces of the bushing 9.

[0051] In this embodiment, the inlet pipe connector 10 and the outlet pipe connector 5 are of the same form. An O-ring and a retaining ring are installed at the static sealing groove 19 of the pipe connector. The pipe connector with the sealing element is installed at the inlet and outlet positions of the outer cylinder 3. The pipe connector is fixed to the outer cylinder 3 with an internal hex screw 4, so that the working medium passes through the pipe connector, through the oil inlet of the outer cylinder and the bushing, and enters and exits the sealing oil cavity.

[0052] In this embodiment, a test verification method for the combined sealing assembly of an aviation hydraulic actuator is also proposed, which specifically includes the following steps:

[0053] Step 1: Inspection of seals before and after the test

[0054] All assembled seals to be verified were visually inspected for appearance quality. Before testing, the surfaces of the seals to be verified were required to be free of obvious burrs, no significant color difference in the material, and no surface damage such as pits or cracks. After testing, no further requirements were made. All assembled seals (including rubber and plastic parts), support rings, and dust scraper rings were dimensionally measured using a universal tool microscope and other tools to check the dimensions of the seals and support rings in their free state, ensuring that the dimensions of the assembled seals were consistent with the drawings. The surface quality (five elements: profile arithmetic mean deviation Ra, profile maximum peak value Rp, profile maximum height Rz, profile support length ratio Tp, and surface inclination Rsk) of the bushing inner surface was measured using a roughness tester and other equipment to ensure that it met the roughness requirements specified in the drawings.

[0055] Step 2: Installation process adaptability

[0056] The combined seal is installed using a hot-installation method into the piston rod combined sealing groove 15 and the partition baffle combined sealing groove 17. The main sealing surface of the combined seal must be free from irreversible deformation damage and bending marks, with a smooth, undamaged surface, and the sealing lip must be free from axial penetration and creases. After the test, the seal is not removed from the test apparatus and can be directly used for functional performance testing.

[0057] Step 3: Sealing performance test

[0058] Based on hydraulic actuator product specifications and other materials, confirm the product testing conditions, including high temperature (T). 高 Low temperature T 低 and high voltage P 高 Low-pressure P 低 .

[0059] After installing the sealing test device on the test bench, start the program. The piston rod will reciprocate within the bushing at least 500 times to complete the break-in test of the combined seal to be verified. Then, start the program again, introduce room temperature oil (15-35℃), and conduct a 3-minute pressure holding test, recording any leakage. Set the reciprocating stroke and frequency according to actual operating conditions to ensure the combined seal is under high pressure (P). 高 and low pressure P 低 The test device was subjected to 200 reciprocating cycles, and the test data was recorded to complete the room temperature performance test. The test apparatus was then placed in a temperature control chamber, and the temperature of the chamber was adjusted to T at a rate of 3℃ / min. 高 After the temperature inside the temperature control chamber stabilizes, maintain this temperature for a period of time, and wait for the combined seals and oil to reach T. 高 And stabilize, first conduct a 3-minute pressure holding test under high pressure and record the leakage situation, then according to the actual working conditions, at P 高 and P 低 The test device was subjected to 200 reciprocating cycles, and leakage test data was recorded to complete the high-temperature performance test. The test apparatus was then placed in a temperature control chamber, and the chamber temperature was adjusted to T at a rate of 3℃ / min. 低 After the temperature inside the temperature control chamber stabilizes, maintain this temperature for a period of time, and wait for the combined seals and oil to reach temperature T. 低 And stabilize, first conduct a 3-minute pressure holding test under high pressure and record the leakage situation, then according to the actual working conditions, at P 高 and P 低 The test device was subjected to 200 reciprocating cycles, and leakage test data was recorded to complete the low-temperature performance test. The test device was installed on the low-pressure static sealing test bench, and 0.02MPa oil pressure was supplied from the oil inlet pipe joint and maintained for 3 minutes. Leakage was recorded to complete the low-pressure static sealing test. The test device was installed on the high-pressure static sealing test bench, and oil pressures of 50%, 100%, and 150% of the actuator's rated working pressure were supplied respectively, maintained for 3 minutes each, and leakage was recorded.

[0060] Step 4: Environmental Adaptability Test

[0061] Five environmental adaptability tests were conducted: low-temperature storage, low-temperature operation, high-temperature storage, high-temperature operation, and temperature shock. The test procedures were carried out in accordance with GJB150A-2009 Military Equipment Laboratory Environmental Test Method. All environmental adaptability tests were conducted with the equipment.

[0062] Among them, low temperature storage, high temperature storage and temperature shock tests require the test device to be naturally filled with working medium without the application of additional hydraulic pressure; low temperature operation and high temperature operation tests require the test device to be filled with working medium at the rated operating pressure.

[0063] Before and after each environmental test, the combined seals are subjected to room temperature performance tests.

[0064] Step 5: Cyclic Life Test

[0065] The normal temperature and high temperature T values ​​are determined based on the proportion of each operating condition throughout the entire life cycle of the hydraulic product being used. 高 Low temperature T 低 The number of reciprocating motion cycles in the reciprocating motion durability test, and the number of cycles in the multi-stage life test (N) 常 Number of reciprocating motions at room temperature, N 高 For the number of reciprocating motions at high temperature, N 低 The number of reciprocating motions at low temperatures.

[0066] Install the test apparatus on the test bench, start the program, set the stroke and frequency of the electric cylinder on the test bench according to the actual working conditions, start the electric cylinder, and the seal P... 高 and P 低 The following reciprocating work N 常 Repeat the test twice, recording any leakage at the end to complete the room temperature reciprocating motion durability test; place the test apparatus in a temperature control chamber and adjust the chamber temperature to T at a rate not exceeding 3℃ / min. 高 After the temperature inside the temperature control chamber stabilizes, wait for the combined seals and oil to reach T. 高 And it is stable. The electric cylinder stroke and frequency are set according to the actual working conditions. The electric cylinder is started, and the high pressure P of the seal is activated. 高 and P 低 The following reciprocating work N 高 Repeat the test twice, recording any leakage at the end to complete the high-temperature reciprocating motion durability test; place the test apparatus in a temperature control chamber and adjust the chamber temperature to T at a rate not exceeding 3℃ / min. 低 After the temperature inside the temperature control chamber stabilizes, wait for the tested seal and oil to reach T. 低 And it is stable. The electric cylinder stroke and frequency are set according to the actual working conditions. The electric cylinder is started, and the high pressure P of the seal is activated. 高 and P 低 The following reciprocating work N 高 / 2 times, record the leakage situation at the end of the test, and complete the low temperature reciprocating motion durability test.

[0067] Step Six: Decomposition and Inspection

[0068] Disassemble and inspect the assembled seals that have completed all test items, and take photos and make written records as evidence.

[0069] A second embodiment of the present invention provides a method for testing and verifying aviation hydraulic actuator components at the component level, using the testing apparatus of the present invention; see reference. Figure 2 As shown in this embodiment, a test verification method for aviation hydraulic actuator components includes the following steps:

[0070] Step 1: Visually inspect the appearance quality of each double-triangle combination seal to be verified. Before the test, the surface of the seal to be verified should be free of obvious burrs, obvious color difference, pits, cracks, and other surface damage. After the test, there are no further requirements. Dimensionally measure each double-triangle combination seal, support ring, and dust scraper ring to be verified using a universal tool microscope and other tools. Check the dimensions of the seal and support ring in their free state to ensure that the dimensions of the combination seal are consistent with the drawings. Use a roughness tester and other equipment to measure the surface quality (five elements: profile arithmetic mean deviation Ra, profile maximum peak value Rp, profile maximum height Rz, profile support length ratio Tp, surface inclination Rsk) of the inner surface of the bushing to ensure that it meets the roughness requirements specified in the drawings.

[0071] Step 2: Using a hot-installation method, install the combined seal into the piston rod combined sealing groove 15 and the partition baffle combined sealing groove 17. The main sealing surface of the combined seal must be free from irreversible deformation damage and bending marks, with a smooth, undamaged surface, and the sealing lip must be free from axial penetration and creases. After the test, the seal is not removed from the test apparatus and can be directly used for functional performance testing.

[0072] Step 3: Based on the product specifications and other materials of the hydraulic actuator, confirm the product test conditions, including high temperature 75℃, low temperature -55℃, high pressure 35MPa, and low pressure 0.02MPa.

[0073] After installing the sealing test device on the test bench, the program was started to make the seal reciprocate 500 times to complete the seal break-in test. Then, the program was started again, and 35MPa room temperature oil was introduced for a 3-minute pressure holding test, recording any leakage. Based on actual working conditions, the reciprocating stroke and frequency were set, making the seal reciprocate 200 times each at high pressure (35MPa) and low pressure (0.02MPa), recording any leakage, completing the room temperature performance test. The test device was then placed in a temperature control chamber, and the temperature was adjusted to 75℃ at a rate of 3℃ / min. After the temperature inside the chamber stabilized, it was kept at that temperature for 2 hours until the combined seal and oil reached and stabilized at 75℃. First, a 3-minute pressure holding test was conducted under high pressure, recording any leakage. Then, based on actual working conditions, the seal reciprocated 200 times at high pressure (35MPa) and low pressure (0.02MPa), recording any leakage. In addition, the high-temperature performance test was completed; the test device was placed in a temperature control chamber, and the temperature of the temperature control chamber was adjusted to -55℃ at a rate of 3℃ / min. After the temperature inside the temperature control chamber stabilized, it was kept at that temperature for 2 hours until the combined sealing components and oil reached and stabilized at -55℃. First, a pressure holding test was carried out under high pressure for 3 minutes, and the leakage was recorded. Then, according to the actual working conditions, the device was operated 200 times under high pressure of 35MPa and low pressure of 0.02MPa, and the leakage was recorded to complete the low-temperature performance test; the test device was installed on a low-pressure static pressure sealing test bench, and 0.02MPa oil pressure was provided and maintained for 3 minutes to complete the low-pressure static sealing test; the test device was installed on a 35MPa high-pressure static sealing test bench, and oil pressures of 50%, 100%, and 150% of the rated working pressure were provided respectively, each for 3 minutes, and the test results were recorded.

[0074] Step 4: Conduct five environmental adaptability tests: low temperature storage, low temperature operation, high temperature storage, high temperature operation, and temperature shock. The test procedures shall be carried out in accordance with GJB150A-2009 Military Equipment Laboratory Environmental Test Method. All environmental adaptability tests shall be conducted with the equipment.

[0075] Among them, low temperature storage, high temperature storage and temperature shock tests require the test device to be naturally filled with working medium without the application of additional hydraulic pressure; low temperature operation and high temperature operation tests require the test device to be filled with working medium at the rated operating pressure.

[0076] Before and after each environmental test, the combined seals are subjected to room temperature performance tests.

[0077] Step 5: Determine the number of reciprocating motions for the durability test of reciprocating motion at normal temperature, high temperature (75℃), and low temperature (-55℃) based on the proportion of each working condition throughout the entire life cycle of the hydraulic product being applied. Conduct multi-stage life tests: 50,000 reciprocating motions at normal temperature, 60,000 reciprocating motions at high temperature, and 30,000 reciprocating motions at low temperature.

[0078] Install the test apparatus on the test bench, start the program, and set the electric cylinder stroke and frequency according to the actual working conditions. Start the electric cylinder and perform 25,000 reciprocating cycles each under 35MPa high pressure and 0.02MPa low pressure on the seals. Record the leakage at the end of the test to complete the room temperature reciprocating motion durability test. Place the test apparatus in a temperature control chamber and adjust the temperature of the temperature control chamber to 75℃ at a rate not exceeding 3℃ / min. After the temperature inside the temperature control chamber stabilizes, continue to maintain the temperature for 2 hours until the combined seals and oil reach 75℃ and stabilize. Set the electric cylinder stroke and frequency according to the actual working conditions, start the electric cylinder, and perform 25,000 reciprocating cycles each under 35MPa high pressure and 0.02MPa low pressure on the seals. The device was subjected to 30,000 reciprocating cycles under both high and low pressure (0.02 MPa). Leakage was recorded at the end of the test, completing the high-temperature reciprocating motion durability test. The test apparatus was then placed in a temperature control chamber, and the chamber temperature was adjusted to -55°C at a rate not exceeding 3°C / min. After the temperature inside the chamber stabilized, it was kept at that temperature for 2 hours until the combined seals and oil reached and stabilized at -55°C. The electric cylinder stroke and frequency were set according to the actual working conditions. The electric cylinder was started, and the seals were subjected to 15,000 reciprocating cycles under both 35 MPa high pressure and 0.02 MPa low pressure. Leakage was recorded at the end of the test, completing the low-temperature reciprocating motion durability test.

[0079] Step 6: Disassemble and inspect the test samples that have completed all the test items, and take photos and make written records.

Claims

1. A method for verifying the reciprocating seal of an aircraft hydraulic actuator, characterized in that, The test is performed using a reciprocating sealing test device, which includes an outer cylinder, a piston rod, and a bushing. The outer cylinder has an oil inlet and an oil outlet. The bushing is coaxially arranged inside the outer cylinder and has a bushing oil passage. The bushing oil passage corresponds to the positions of the oil inlet and the oil outlet of the outer cylinder. The bushing has two inner static sealing grooves on its outer circumference, and the two inner static sealing grooves are symmetrically arranged on both sides of the bushing oil inlet. The inner static sealing grooves are equipped with O-rings and retaining rings. The outer static sealing grooves at both ends of the bushing are provided with outer static sealing grooves, and the outer static sealing grooves are equipped with O-rings and retaining rings. The piston rod is slidably disposed within the bushing. Piston rod combination sealing grooves are provided on the outer circular surfaces at both ends of the piston rod. From the inside to the outside, a partition baffle and an end cap are sequentially sleeved on both ends of the piston rod. A piston rod support ring groove is formed between the end face of the partition baffle near the piston rod combination sealing groove and the piston rod. A combination seal is provided in the piston rod combination sealing groove, and a support ring is provided in the piston rod support ring groove. The inner circular surface of the partition baffle is provided with a static sealing groove, the outer circular surface is provided with a combined sealing groove, the combined sealing groove of the partition baffle is provided with a combined sealing element, and the static sealing groove of the partition baffle is provided with an O-ring and a retaining ring. The inner circular surface of the end cap is provided with a static sealing groove, and the outer circular surface is provided with a dust scraper groove. The static sealing groove of the end cap is provided with an O-ring and a retaining ring, and the dust scraper groove is provided with a dust scraper ring. The reciprocating seal test verification method includes sealing characteristic test, environmental adaptability test and reciprocating life test of the combined seal; The sealing performance test of the combined seal includes the following steps: Step 11: Confirm the test conditions according to the hydraulic actuator product specifications, including the high temperature T. 高 Low temperature T 低 and high voltage P 高 Low-pressure P 低 ; Step 12: Install the sealing test device on the test bench, start the program, and the piston rod reciprocates within the bushing at least 500 times to complete the break-in test of the combined seal to be verified, and then end the program. Step 13: Restart the program and introduce 15~35℃ room temperature oil into the sealing oil chamber between the bushing and the piston rod through the oil inlet pipe joint. Close the oil outlet pipe joint and conduct a 3-minute pressure holding test. Record the leakage situation. Step 14: Set the reciprocating stroke and frequency according to the actual working conditions, so that the combined seal to be verified is under high pressure P. 高 and low pressure P 低 The lower piston rod reciprocated 200 times each, and the test data was recorded to complete the room temperature performance test; Step 15: Place the test apparatus in the temperature control chamber and adjust the temperature of the chamber to T at a rate of 3℃ / min. 高 After the temperature inside the temperature control chamber stabilizes, maintain this temperature for a period of time, and wait for the combined seals and oil to reach T. 高 And stabilize, conduct a 3-minute pressure holding test under high pressure, and record the leakage situation; Step 16: Based on the actual working conditions, in P 高 and P 低 The lower piston rod reciprocates 200 times each, and the leakage test data is recorded to complete the high-temperature performance test; Step 17: Place the test apparatus in the temperature control chamber and adjust the temperature of the chamber to T at a rate of 3℃ / min. 低 After the temperature inside the temperature control chamber stabilizes, maintain this temperature for a period of time, and wait for the combined seals and oil to reach temperature T. 低 And stabilize, conduct a 3-minute pressure holding test under high pressure, and record the leakage situation; Step 18: Based on the actual working conditions, in P 高 and P 低 The lower piston rod reciprocates 200 times each, and the leakage test data is recorded to complete the low-temperature performance test; Step 19: Install the test device on the low-pressure static sealing test bench, connect the oil with a pressure of 0.02MPa from the inlet pipe and maintain it for 3 minutes, record the leakage, and complete the low-pressure static sealing test; install the test device on the high-pressure static sealing test bench, provide oil pressure of 50%, 100% and 150% of the rated working pressure of the actuator respectively, maintain each for 3 minutes, and record the leakage.

2. The method according to claim 1, characterized in that, The aforementioned partition baffle and end cap are locked to the outer circular surfaces at both ends of the piston rod by nuts.

3. The method according to claim 1, characterized in that, The oil inlet of the outer cylinder is fitted with an oil inlet pipe connector via an internal hexagon screw, and the oil outlet of the outer cylinder is fitted with an oil outlet pipe connector via an internal hexagon screw. A static sealing groove is provided on the outer circular surface of the oil inlet pipe connector that contacts the inner wall of the oil inlet of the outer cylinder, and a static sealing groove is provided on the outer circular surface of the oil outlet pipe connector that contacts the inner wall of the oil outlet of the outer cylinder. An O-ring and a retaining ring are provided in the static sealing groove of the pipe connector.

4. The method according to claim 1, characterized in that, Limiting blocks are provided on both sides of the outer cylinder to limit the bushing.

5. The method according to claim 4, characterized in that, The outer cylinder is provided with oil leakage ports at both ends, and the oil leakage ports are located between the inner end face of the limiting block and the outer end face of the bushing.

6. The method according to claim 5, characterized in that, The environmental adaptability test of the combined seal is as follows: five environmental adaptability tests are carried out, namely low temperature storage, low temperature operation, high temperature storage, high temperature operation, and temperature shock. The test procedures are carried out in accordance with GJB150A-2009 Military Equipment Laboratory Environmental Test Method. All environmental adaptability tests are conducted by installing the combined seal on the test device. Among them, the low temperature storage, high temperature storage and temperature shock tests require the test device to be naturally filled with the working medium without the application of additional hydraulic pressure; the low temperature operation and high temperature operation tests require the test device to be filled with the working medium at the rated operating pressure. Before and after each environmental adaptability test, the combined seals are subjected to a room temperature performance test.

7. The method according to claim 6, characterized in that, The cyclic life test of the combined seal includes the following steps: Step 21: Determine the normal temperature and high temperature T based on the proportion of each operating condition throughout the entire life cycle of the hydraulic product using the combined seal. 高 Low temperature T 低 The number of reciprocating motion cycles in the reciprocating motion durability test is used to conduct a multi-stage life test, and N is defined as... 常 Number of reciprocating motions at room temperature, N 高 For the number of reciprocating motions at high temperature, N 低 This represents the number of reciprocating motions at low temperatures. Step 22: Install the test apparatus on the test bench, start the program, set the stroke and frequency of the electric cylinder on the test bench according to the actual working conditions, start the electric cylinder, and the combined seal to be verified is at P 高 and P 低 The following reciprocating work N 常 / 2 times, record the leakage situation at the end of the test, and complete the room temperature reciprocating motion durability test; Step 23: Place the test apparatus in the temperature control chamber and adjust the temperature of the chamber to T at a rate not exceeding 3℃ / min. 高 After the temperature inside the temperature control chamber stabilizes, wait for the combined seals and oil to reach T. 高 And stabilize, the electric cylinder stroke and frequency are set according to the actual working conditions, the electric cylinder is started, and the combined seals are under high pressure P. 高 and P 低 The following reciprocating work N 高 / 2 times, record the leakage situation at the end of the test, and complete the high temperature reciprocating motion durability test; Step 24: Place the test apparatus in the temperature control chamber and adjust the temperature of the chamber to T at a rate not exceeding 3℃ / min. 低 After the temperature inside the temperature control chamber stabilizes, wait for the combined seals and oil to reach T. 低 And stabilize, the electric cylinder stroke and frequency are set according to the actual working conditions, the electric cylinder is started, and the combined seals are under high pressure P. 高 and P 低 The following reciprocating work N 高 / 2 times, record the leakage situation at the end of the test, and complete the low temperature reciprocating motion durability test.

8. The method according to claim 7, characterized in that, The assembled seals that have completed sealing characteristic tests, environmental adaptability tests, and cyclic life tests are disassembled for inspection, photographed for evidence, and recorded.

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