An efficient exhaust system and method for a landing gear buffer

Abstract

The present invention relates to an efficient exhaust system and method for a landing gear buffer. The efficient exhaust system mainly includes a negative pressure exhaust unit, a positive pressure oil injection unit and a control system. Among them, the negative pressure exhaust unit is composed of a vacuum pump, a vacuum gauge, a stop valve, an oil-gas separator, etc. By controlling the vacuum pump through the control system and combining with the oil-gas separator, rapid automatic exhaust of the landing gear buffer is achieved; the positive pressure oil injection unit is composed of a booster cylinder, a stop valve, etc. By controlling the booster cylinder through the system, automatic oil injection into the landing gear buffer is realized. The greatest contribution of the present invention lies in creating an automated / semi-automated efficient exhaust method and device for the landing gear buffer, solving the problem of low efficiency of manual exhaust of the landing gear buffer, and greatly improving the efficiency of exhaust and oil injection.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft landing gear ground tests, and is applied to the exhaust of buffers in the static strength, fatigue, and functional reliability tests of landing gears. Specifically, it relates to a high-efficiency exhaust system and method for landing gear buffers. Background Art

[0002] The static, fatigue, and functional reliability tests of landing gears are key steps to ensure the rationality of their design and analysis methods. At the same time, they also help to evaluate the accuracy of manufacturing processes, identify potential defects, and provide a basis for formulating scientific maintenance and repair plans. These tests are crucial for ensuring the safe operation of aircraft.

[0003] The static, fatigue, and functional reliability tests of landing gears are necessary ways to verify the design and analysis methods, manufacturing processes, expose defects, and formulate maintenance plans of landing gears. Before the landing gear test, it is necessary to discharge the air in the landing gear buffer and inject hydraulic oil at the same time, so that the landing gear buffer remains in an oil-filled state under the specified compression amount of the test. Currently, the manual exhaust method is usually adopted. Based on the characteristics of low gas density and high hydraulic oil density, the gas in the buffer is replaced by gravity, and the exhaust is achieved through repeated replacement. This manual exhaust method takes a long time, generally requiring about 10 days to 1 month. The exhaust time and effect are related to the experience of technicians, which is not conducive to the development of multi-landing gear test tasks. For landing gears with complex buffer cavities, manual exhaust is difficult and the effect is not good.

[0004] To improve the exhaust efficiency of landing gears and meet the high-efficiency exhaust requirements of buffers with different configurations, an "efficient exhaust method and device for landing gear buffers" is invented to achieve mechanical automation and semi-automation in the exhaust process of landing gear buffers. On the premise of ensuring that the exhaust of the landing gear buffer is completely qualified, the present invention shortens the exhaust time to within 1 day, and the exhaust efficiency of the landing gear buffer is increased by more than 80%. It has the advantages of fast efficacy, high drainage rate, simple use, and short time consumption. Summary of the Invention

[0005] To solve the above problems, the present invention discloses a buffer exhaust system that can be used for the static, fatigue, and functional reliability tests of landing gears, which can achieve mechanical automation and semi-automation in the exhaust process of landing gear buffers, greatly shortening the exhaust time and improving the exhaust quality.

[0006] A high-efficiency exhaust system for landing gear buffers includes:

[0007] A landing gear equipped with an oil injection nozzle thimble valve for controlling the oil cavity switch;

[0008] A positive-pressure oil injection unit and a negative-pressure exhaust unit for injecting hydraulic oil and extracting gas respectively;

[0009] A control system for coordinating the injection and extraction actions of a positive-pressure oil injection unit and a negative-pressure exhaust unit;

[0010] Wherein, an A-end cut-off valve and a B-end cut-off valve are provided at the oil injection nozzle thimble valve, forming two independent branches. The first branch includes an oil pipe exhaust valve, an A-end cut-off valve and a positive-pressure oil injection unit. By closing the oil injection nozzle thimble valve, opening the oil pipe exhaust valve and the A-end cut-off valve through the control system, the positive-pressure oil injection unit is used to fill the oil injection pipeline with oil and discharge air. The second branch includes a B-end cut-off valve, a negative-pressure exhaust unit and an oil drain valve. By opening the oil injection nozzle thimble valve, the B-end cut-off valve and the oil drain valve through the control system, the negative-pressure exhaust unit is used to provide negative pressure, so that the gas in the landing gear oil cavity is discharged together with the oil.

[0011] Preferably, the landing gear is equipped with a support device for supporting and adjusting the attitude of the landing gear, and the attitude of the landing gear is adjusted when necessary to make the oil cavity thimble valve at a high position.

[0012] Preferably, the positive-pressure oil injection unit includes a booster cylinder, a hydraulic oil source, a pressure sensor and a hydraulic control valve, providing sufficient pressure to supply the oil required for the negative-pressure exhaust and positive-pressure oil injection processes of the buffer.

[0013] Preferably, the negative-pressure exhaust unit includes a vacuum pump, a pneumatic control valve and a pneumatic sensor, providing the negative pressure required for the negative-pressure oil drainage process.

[0014] Preferably, one or more of an oil-gas separator, a gas cut-off valve and a vacuum gauge are further provided on the pipeline between the B-end cut-off valve and the negative-pressure exhaust unit. The oil-gas separator is used to separate the mixed oil, the gas cut-off valve is used to control the gas discharge, and the vacuum gauge is used to monitor the vacuum degree in the system to monitor whether the system fails.

[0015] Preferably, the oil-gas separator is arranged downstream of the B-end cut-off valve, and the pipeline between the B-end cut-off valve and the oil-gas separator is a long transparent tube, serving as an observation window to feedback the exhaust end signal.

[0016] Preferably, the control system receives and processes the sensor feedback signal, and issues a control command to control the oil injection and exhaust operations of the positive-pressure oil injection unit 8 and the negative-pressure exhaust unit 9, including switching and setting the pressure value.

[0017] An exhaust method for an efficient exhaust system of a landing gear buffer, including:

[0018] Step 1, open the oil pipe exhaust valve and the A-end cut-off valve 5. At this time, the buffer oil injection nozzle thimble valve 3 is closed, and the positive-pressure oil injection unit 8 is controlled by the control system 7 to inject oil until the oil injection pipeline is completely filled with oil and all the internal air is discharged, and then the oil pipe exhaust valve (4) and the A-end cut-off valve (5) are closed;

[0019] Step 2: Synchronously open the buffer nozzle thimble valve 3, B-end cut-off valve 6, and oil drain valve 14. Control the negative pressure exhaust unit 9 through the control system 7 to provide negative pressure, so that the gas in the landing gear oil cavity is discharged together with the oil; the oil-gas separator 10 separates and processes the mixed oil until there are no bubbles and liquid flow in the transparent pipe between the B-end cut-off valve 6 and the oil-gas separator 10.

[0020] Step 3: Close the B-end cut-off valve 6, reopen the A-end cut-off valve 5, and inject oil into the landing gear 1 through the positive pressure oil injection unit 8 until the oil pressure reaches the preset level and the landing gear is fully extended; close each valve, and the exhaust and oil injection are completed.

[0021] The beneficial effects of the present invention are as follows:

[0022] Realize the mechanical automation and semi-automation of the exhaust process of the landing gear buffer. By setting the pressure values of the high-pressure chamber and the vacuum pump through the control system, the control of the exhaust process is more accurate, improving the exhaust quality of the landing gear buffer and ensuring safety during the exhaust process.

[0023] Greatly improve the exhaust efficiency of the landing gear, reducing a large amount of preparation time for the static, fatigue, and functional reliability tests of the landing gear.

[0024] It has strong versatility and a wide application range. The same set of equipment can be used for different types of landing gears. At the same time, the oil discharged during the exhaust process is recycled, which can save resources and reduce costs.

[0025] When operating in a high-pressure environment, it is crucial to prevent oil backflow or leakage. This application incorporates multiple protective measures such as gas cut-off valves and oil drain valves in the design and optimizes the pipeline connection structure, effectively avoiding potential problems caused by pressure fluctuations and enhancing the overall safety of the system.

[0026] In the negative pressure suction branch, traditional methods often cannot completely remove the tiny bubbles in the oil, affecting the exhaust effect. Whether the oil-gas separator introduced in this application has innovative points, combined with the design of the long transparent pipe, provides intuitive monitoring of the exhaust state, greatly improving the oil-gas separation efficiency and ensuring the thoroughness of the exhaust. Description of the Drawings

[0027] Figure 1 High-efficiency exhaust system for landing gear buffer.

[0028] Reference numerals: 1 - landing gear body, 2 - support device, 3 - buffer nozzle thimble valve, 4 - tubing exhaust valve, 5 - A-end cut-off valve, 6 - B-end cut-off valve, 7 - control system, 8 - positive pressure oil injection unit, 9 - negative pressure exhaust unit, 10 - oil-gas separator, 11 - vacuum gauge, 12 - fuel tank, 13 - gas cut-off valve, 14 - oil drain valve. Detailed Embodiments

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Embodiment

[0030] The following further elaborates on the present invention:

[0031] As Figure 1 shown, the present invention discloses an efficient exhaust system for a landing gear buffer, including a landing gear 1, a negative pressure exhaust unit 9, a positive pressure oil injection unit 8, and a control system 7. The landing gear 1 is a carrier for the retraction and extension of the buffer. The buffer oil injection nozzle thimble valve 3 is used to control the opening and closing of the high-pressure chamber and the low-pressure chamber, and should be kept open during the exhaust process. In this embodiment, in order to ensure the optimal position of the landing gear during the exhaust process, a support device 2 is assembled thereon to adjust the attitude of the landing gear and ensure that the oil chamber nozzle thimble valve is at a high position, so as to effectively discharge the air in the pipeline. The buffer oil injection nozzle thimble valve 3 is installed with oil pipes and stop valves, including an A-end stop valve 5 and a B-end stop valve 6, which are respectively connected to the positive pressure oil injection unit 8 and the negative pressure exhaust unit 9, forming two independent working paths:

[0032] The first branch includes an oil pipe exhaust valve 4, an A-end stop valve 5, and a positive pressure oil injection unit 8, which is responsible for injecting hydraulic oil into the landing gear 1 and discharging the air above during the oil injection process. Among them, the oil pipe exhaust valve 4 is used to control the exhaust of the oil delivery pipeline; the A-end stop valve 5 connects the positive pressure oil injection unit 8 and the landing gear 1, and is used to control the connection between the booster cylinder and the inner cavity of the buffer; the positive pressure oil injection unit 8 is used to inject hydraulic oil into the landing gear 1. The positive pressure oil injection unit 8 contains a booster cylinder, a hydraulic oil source, a pressure sensor, and a hydraulic control valve, and provides sufficient pressure to supply the oil required for the negative pressure exhaust and positive pressure oil injection processes of the buffer.

[0033] The second branch includes a B-end cut-off valve 6, an oil drain valve 14, and a negative pressure exhaust unit 9, which are used to extract and separate the oil-gas mixture inside the buffer. An oil-gas separator is provided in this path, which can guide the oil to the fuel tank for storage, prevent the oil from flowing back through the gas cut-off valve, and monitor the negative pressure value using a vacuum gauge. Among them, the B-end cut-off valve 6 connects the negative pressure exhaust unit 9 and the landing gear 1 to control the connection between the vacuum pump and the buffer cavity; the oil drain valve 14 is used to finally discharge the processed oil. The negative pressure exhaust unit includes a vacuum pump, a pneumatic control valve, and a pneumatic sensor, providing a stable negative pressure environment for the suction process. When the control system 7 controls the negative pressure exhaust unit 9 to perform a negative pressure operation, the oil is extracted and gas-liquid separation is carried out to achieve the exhaust function. In this embodiment, an oil-gas separator 10 is provided downstream of the B-end cut-off valve 6. The outlet of the oil-gas separator 10 is divided into two paths according to the separated oil and gas. One path is sequentially connected to the oil drain valve 14 and the fuel tank 12 to discharge and store the separated oil; the other path is sequentially connected to the gas cut-off valve 13, the vacuum gauge 11, and the negative pressure exhaust unit 9. Among them,

[0034] The oil-gas separator 10 is used to separate the oil-gas mixture extracted by the negative pressure exhaust unit 9. At the same time, it can also control the vacuum pumping process. In this embodiment, the oil-gas separator 10 is provided downstream of the B-end cut-off valve 6, and the pipeline between the B-end cut-off valve 6 and the oil-gas separator 10 is a long transparent tube, serving as an observation window to feedback the exhaust end signal. The design of the oil-gas separator 10 combined with the long transparent tube provides intuitive monitoring of the exhaust state, greatly improving the oil-gas separation efficiency and ensuring the thoroughness of exhaust. The vacuum gauge 11 is used to monitor the negative pressure value of the negative pressure exhaust unit 9 on-site, the fuel tank 12 is used to collect the extracted oil, the gas cut-off valve 13 is used to further prevent the oil from flowing into the vacuum pipeline during vacuum pumping, facilitating on-site operation, and the oil drain valve 14 is used to control the opening and closing of oil drainage; the negative pressure exhaust unit 9 includes a vacuum pump, a pneumatic control valve, and a pneumatic sensor, providing the required negative pressure for the negative pressure oil drainage process.

[0035] The entire system is uniformly scheduled by the control system 7 to ensure that each component works in coordination to achieve efficient and safe exhaust and oil injection operations. Embodiment

[0036] This embodiment discloses a working method of an efficient exhaust system for a landing gear buffer, based on the efficient exhaust system for a landing gear buffer in Embodiment 1.

[0037] Before exhaust, support and adjust the attitude of the landing gear 1 through the support device 2 so that the oil cavity nozzle needle valve 3 of the landing gear 1 is at a high position. During negative pressure exhaust:

[0038] (a) Open the thimble valves 3 of the landing gear buffer oil nozzles separately. Install a set of oil pipes with stop valves at the A and B interfaces of each thimble valve, namely the A-end stop valve 5 and the B-end stop valve 6. The A-end oil pipe is connected to the booster cylinder, and the outlet of the B-end stop valve 6 is connected with a transparent pipe.

[0039] (b) Rotate the thimble valve 3 of the buffer oil nozzle clockwise, open the oil pipe exhaust valve 4 and the A-end stop valve 5, so that the oil and gas in the oil pipe are discharged from the oil pipe exhaust valve 4 into the fuel tank 12.

[0040] (c) Install an oil-gas separator 10 between the vacuum pump air pipe of the negative pressure exhaust unit 9, the vacuum gauge 11 and the B-end pipe. Connect with a longer transparent air pipe, the vacuum gauge 11 and the vacuum pump air pipe, and close the valve at the oil-gas separator 10.

[0041] (d) Open the thimble valve 3 of the buffer oil nozzle, and then open the B-end stop valve 6 and the oil drain valve 14.

[0042] (e) Slowly open the air stop valve 13, and control the negative pressure exhaust unit 9 to draw negative pressure through the control system 7 at a fixed value, so that the oil and gas are separated by the oil-gas separator 10. At the same time, observe the flow of the red oil and the situation of bubbles in the front transparent air pipe. Until there are no bubbles and liquid flow in the transparent air pipe, rotate the thimble valve 3 of the buffer oil nozzle counterclockwise to close it, and then close the B-end stop valve 6 and the valve at the oil-gas separator 10. 4]

[0043] (f) Repeat the operations in e) and f) (generally 2 - 3 times are enough), until the oil in the transparent air pipe is static and there are no tiny bubbles, then the exhaust work is completed.

[0044] During positive pressure oil injection, open the thimble valve 3 of the landing gear buffer oil nozzle, and the positive pressure oil injection unit 8 injects oil slowly. When the oil pressure rises, open the A-end stop valve 5. The positive pressure oil injection unit 8 injects oil slowly again until the oil pressure rises significantly and the piston rod of the landing gear 1 extends. Then rotate the thimble valve 3 of the buffer oil nozzle counterclockwise to close it. At this time, the exhaust and oil injection of the buffer are completed.

[0045] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An efficient exhaust system for a landing gear buffer, characterized in that, Comprising: A landing gear (1) equipped with a grease nipple thimble valve (3) for controlling the opening and closing of an oil chamber; A positive pressure oil injection unit (8) and a negative pressure exhaust unit (9) for injecting hydraulic oil and extracting gas respectively; A control system (7) for coordinating the injection and extraction actions of the positive pressure oil injection unit (8) and the negative pressure exhaust unit (9); Wherein, an A-end stop valve (5) and a B-end stop valve (6) are provided at the grease nipple thimble valve (3) to form two independent branches. The first branch includes an oil pipe exhaust valve (4), an A-end stop valve (5) and a positive pressure oil injection unit (8). By closing the grease nipple thimble valve (3), opening the oil pipe exhaust valve (4) and the A-end stop valve (5) through the control system, the positive pressure oil injection unit (8) is used to fill the oil injection pipeline with oil and discharge air. The second branch includes a B-end stop valve (6), a negative pressure exhaust unit (9) and an oil drain valve (14). By opening the grease nipple thimble valve (3), the B-end stop valve (6) and the oil drain valve (14) through the control system (7), the negative pressure exhaust unit (9) is used to provide negative pressure so that the gas in the landing gear oil chamber is discharged together with the oil.

2. The high-efficiency exhaust system for a landing gear buffer according to claim 1, characterized in that, The landing gear (1) is equipped with a support device (2) for supporting and adjusting the attitude of the landing gear (1), and adjusting the attitude of the landing gear to make the oil chamber thimble valve (3) at a high position.

3. The high-efficiency exhaust system of the landing gear buffer according to claim 1, characterized in that The positive pressure oil injection unit (8) includes a booster cylinder, a hydraulic oil source, a pressure sensor and a hydraulic control valve, and provides sufficient pressure to supply the oil required for the negative pressure exhaust and positive pressure oil injection processes of the buffer.

4. The high-efficiency exhaust system for the landing gear buffer according to claim 1, characterized in that The negative pressure exhaust unit (9) includes a vacuum pump, a pneumatic control valve and a pneumatic sensor, and provides the negative pressure required for the negative pressure oil drainage process.

5. The high-efficiency exhaust system for a landing gear buffer according to claim 1, wherein, One or more of an oil-gas separator (10), a gas stop valve (13) and a vacuum gauge (11) are further provided on the pipeline between the B-end stop valve 6 and the negative pressure exhaust unit (9). The oil-gas separator (10) is used to separate the mixed oil, the gas stop valve (13) is used to control the gas discharge, and the vacuum gauge (11) is used to monitor the vacuum degree in the system to monitor whether the system fails.

6. The high-efficiency exhaust system for the landing gear buffer according to claim 5, characterized in that, The oil-gas separator (10) is provided downstream of the B-end stop valve (6), and the pipeline between the B-end stop valve (6) and the oil-gas separator (10) is a long transparent tube, serving as an observation window to feedback the exhaust end signal.

7. The high-efficiency exhaust system of the landing gear buffer according to claim 1, characterized in that, The control system (7) receives and processes the sensor feedback signal, and issues a control command to control the oil injection and exhaust operations of the positive pressure oil injection unit (8) and the negative pressure exhaust unit (9), including switching and setting the pressure value.

8. An exhaust method for an efficient exhaust system of a landing gear buffer, characterized in that, The exhaust system according to any one of claims 1-7, comprising: Step 1: Open the oil pipe exhaust valve (4) and the A-end stop valve (5). At this time, the grease nipple thimble valve (3) of the buffer is closed. Control the positive pressure oil injection unit (8) to inject oil through the control system (7) until the oil injection pipeline is completely filled with oil and all the internal air is discharged, and then close the oil pipe exhaust valve (4) and the A-end stop valve (5). Step 2: Simultaneously open the buffer oil nozzle thimble valve (3), the B-end stop valve (6) and the oil drain valve (14). Control the negative pressure exhaust unit (9) through the control system (7) to provide negative pressure, so that the gas in the landing gear oil cavity is discharged together with the oil. The oil-gas separator (10) separates the mixed oil until there are no bubbles and liquid flow in the transparent pipe between the B-end stop valve (6) and the oil-gas separator (10). Step 3: Close the B-end stop valve (6), reopen the A-end stop valve (5), and inject oil into the landing gear (1) through the positive pressure oil injection unit (8) until the oil pressure reaches the preset level and the landing gear is fully extended. Close each valve to end the exhaust and oil injection.

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