An emergency oil supply system for the bearing cavity of an aircraft engine

Abstract

This application belongs to the field of aero-engine technology, and specifically relates to an emergency lubrication system for aero-engine bearing cavities. The system includes a bearing cavity sealing bleed air pipe, a throttle nozzle, an oil supply pipe, an auxiliary oil supply mechanism, and a nozzle. Its core lies in the auxiliary oil supply mechanism, which houses an oil reservoir with a piston. The throttle nozzle precisely controls the sealing bleed air pressure, maintaining it within a specific range between the "oil supply pressure" and the "bearing cavity pressure." During normal engine operation, the oil supply pressure overcomes the one-way valve to fill the oil reservoir. When the aircraft reverses flight or experiences overload causing a interruption in the main oil supply and a sudden drop in oil supply pressure, the high-pressure gas in the sealing bleed air pipe automatically pushes the piston, forcibly pumping the reserve lubricating oil into the bearing cavity. This invention utilizes the engine's own air pressure difference as power, eliminating the need for an external power source or complex ejector pump. This simplifies the structure and increases reliability, effectively ensuring continuous bearing lubrication under extreme conditions and significantly reducing the risk of engine failure.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to an emergency oil supply system for lubricating oil in the bearing cavity of an aero-engine. Background Technology

[0002] Under extreme operating conditions such as inverted flight and overload, aircraft engines may experience interruptions in lubrication supply to the bearing cavity. For bearings with high speed and high load requirements within the bearing cavity, there is a risk of operational failure during lubrication interruptions. Therefore, it is necessary to study a design scheme that can provide emergency lubrication to the bearing during lubrication interruptions to ensure reliable bearing operation and reduce engine operational risks.

[0003] Domestic and international research on emergency oil supply systems for bearing cavities mainly adopts the ejection principle, which draws out the lubricating oil in the emergency oil tank through the high-pressure gas ejection effect to form an oil-gas transport and deliver it to the emergency oil supply circuit. This includes high-pressure gas nozzles, injectors, mixing chambers, diffusers, delivery pipelines, and emergency oil tanks, etc. The structure is complex, the cost is high, and it is difficult to achieve emergency oil supply in the limited space of the bearing cavity. Summary of the Invention

[0004] To solve the above problems, this application provides an emergency oil supply system for lubricating oil in the bearing cavity of an aero-engine, characterized in that it includes a bearing cavity sealing vent pipe (1), a throttle nozzle (2), a bearing cavity oil supply pipe (3), a bearing cavity oil supply nozzle (4), a one-way valve (5), an auxiliary oil supply mechanism (6), and an emergency oil supply nozzle (7).

[0005] The auxiliary oil supply mechanism (6) is equipped with an oil storage tank. The oil storage tank has an inlet and an outlet. The inlet is connected to the first branch of the bearing cavity oil supply pipe (3) through a one-way valve (5). The outlet is connected to the emergency oil supply nozzle (7). The second branch of the bearing cavity oil supply pipe (3) is connected to the bearing cavity oil supply nozzle (4).

[0006] The oil storage tank is equipped with a movable piston, which divides the interior of the oil storage tank into a lubricating oil chamber and a pneumatic chamber. The lubricating oil chamber is connected to the inlet and outlet of the oil storage tank, and the pneumatic chamber is connected to the bearing cavity sealing air pipe (1) through a throttle nozzle (2).

[0007] Preferably, during engine start-up and normal operation, the pressure of the bearing cavity oil supply pipe (3) is greater than the pressure of the bearing cavity sealing sump pipe (1), and the lubricating oil overcomes the opening pressure of the one-way valve (5) to enter the oil reservoir, pushing the piston to move to store the lubricating oil.

[0008] Preferably, when the pressure in the bearing cavity oil supply pipe (3) drops to less than the pressure in the bearing cavity sealing sump pipe (1) due to engine overrun or overload, the high-pressure gas in the bearing cavity sealing sump pipe (1) acts on the piston through the throttle nozzle (2), pushing the piston to pump the lubricating oil in the oil reservoir into the bearing cavity through the emergency oil supply nozzle (7).

[0009] Preferably, the displacement stroke of the piston is matched with the volume of the oil reservoir, and the volume of the oil reservoir is designed based on the preset lubricating oil interruption time and emergency oil supply.

[0010] Preferably, the throttle nozzle (2) is configured to ensure that the pressure in the pneumatic chamber always meets the following condition: P bearing chamber oil supply pipe > P pneumatic chamber > P bearing chamber.

[0011] Preferably, the one-way valve (5) is configured to prevent the lubricating oil in the oil reservoir from flowing back into the oil supply pipe (3) of the bearing cavity, and to remain closed during lubricating oil interruption.

[0012] Preferably, the auxiliary oil supply mechanism (6) is integrated and installed inside the bearing cavity.

[0013] Preferably, during normal engine operation, the bearing cavity oil supply nozzle (4) and the emergency oil supply nozzle (7) supply oil to the bearing cavity simultaneously, wherein the sum of the oil supply from the emergency oil supply nozzle (7) and the oil supply from the bearing cavity oil supply nozzle (4) is the total amount of lubricating oil required by the bearing cavity.

[0014] Preferably, the cross-sectional area of ​​the piston is larger than the equivalent flow area of ​​the emergency oil supply nozzle (7) to ensure that the piston can pump out a sufficient amount of lubricating oil per unit time.

[0015] The bearing cavity emergency oil supply system designed in this invention has a simple structure and can be installed inside the bearing cavity to provide local emergency oil supply to bearings with high speed and high load requirements during the interruption of lubrication. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an emergency oil supply system for the bearing cavity of an aircraft engine. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings. Figure 1 As shown, an emergency lubrication system for an aero-engine bearing cavity is described. A schematic diagram of the system is shown below. Figure 1 It includes a bearing cavity sealing vent pipe (1), a throttle nozzle (2), a bearing cavity oil supply pipe (3), a bearing cavity oil supply nozzle (4), a one-way valve (5), an auxiliary oil supply mechanism (6), and an emergency oil supply nozzle (7). The working principle is as follows:

[0018] The bearing cavity oil supply pipe (3) is divided into two branches. One branch is connected to the bearing cavity oil supply nozzle (4), and the other branch is connected to one inlet of the auxiliary oil supply mechanism (6) through a one-way valve (5). The other inlet of the auxiliary oil supply mechanism (6) is connected to the bearing cavity sealing vent pipe (1) through a throttle nozzle (2). The outlet of the auxiliary oil supply mechanism (6) is connected to the emergency oil supply nozzle (7). Both the emergency oil supply nozzle (7) and the bearing cavity oil supply nozzle (4) are connected to the bearing cavity. The auxiliary oil supply mechanism (6) has an oil storage tank inside. The inlet of the oil storage tank is connected to the first inlet. The outlet is connected to the outlet of the auxiliary oil supply mechanism (6). The oil tank is equipped with a piston. The piston is driven by the pressure difference between the second inlet of the auxiliary oil supply mechanism (6) and the oil tank. The throttle nozzle (2) controls the bearing cavity sealing air pipe (1) to be less than the bearing cavity oil supply pipe (3) and greater than the bearing cavity pressure. When the bearing cavity oil supply pipe (3) cannot pump oil due to the aircraft attitude, and the pressure decreases to below the pressure of the bearing cavity sealing air pipe (1), the air pressure of the bearing cavity sealing air pipe (1) pushes the piston to pump the lubricating oil in the oil tank into the bearing cavity.

[0019] Specifically:

[0020] During engine start-up, the oil supply pressure in the bearing cavity overcomes the opening pressure of the one-way valve (5) and fills the auxiliary oil supply mechanism (6) with lubricating oil. The oil supply pressure during engine start-up is greater than the sealing pressure of the bearing cavity, so lubricating oil can be filled into the auxiliary oil supply mechanism.

[0021] During normal engine operation, in addition to supplying lubricating oil to the bearing oil supply nozzle, oil is also supplied to the emergency oil supply nozzle. The sum of the oil supply from the two nozzles is the amount of lubricating oil required by the bearings, sealing devices, etc.

[0022] During normal engine operation, considering that the sealing pressure of the bearing cavity may be higher than the oil supply pressure of the bearing cavity in some high-altitude states, a throttle nozzle is installed on the bearing cavity sealing air vent pipe to reduce the sealing pressure and ensure that the auxiliary oil supply mechanism can be filled with lubricating oil in all operating states.

[0023] When engine lubrication is interrupted due to factors such as attitude or overload, the auxiliary oil supply mechanism supplies oil to the emergency oil supply nozzle under the sealing pressure of the bearing cavity. The oil supply pressure difference is equal to the bearing cavity sealing pressure difference (the difference between the bearing cavity sealing pressure and the bearing cavity pressure). During the engine lubrication interruption, the bearing cavity sealing pressure difference remains positive, thus ensuring reliable oil supply. Furthermore, a one-way valve prevents oil from being supplied to other parts during the lubrication interruption.

[0024] During engine shutdown, as the fuel supply pressure and sealing pressure decrease, the emergency nozzle switches from supplying fuel to stopping fuel supply. During this period, the return pump continues to work, which can ensure that the change in engine intake volume is small.

[0025] The volume of the auxiliary oil supply mechanism and the size of the emergency nozzle can be designed according to the oil interruption time and the oil supply pressure differential of the auxiliary oil supply mechanism to ensure continuous and reliable oil supply during the oil interruption period.

[0026] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An emergency lubrication system for an aero-engine bearing cavity, characterized in that, It includes a bearing cavity sealing air vent pipe (1), a throttle nozzle (2), a bearing cavity oil supply pipe (3), a bearing cavity oil supply nozzle (4), a one-way valve (5), an auxiliary oil supply mechanism (6), and an emergency oil supply nozzle (7). The auxiliary oil supply mechanism (6) is equipped with an oil storage tank. The oil storage tank has an inlet and an outlet. The inlet is connected to the first branch of the bearing cavity oil supply pipe (3) through a one-way valve (5). The outlet is connected to the emergency oil supply nozzle (7). The second branch of the bearing cavity oil supply pipe (3) is connected to the bearing cavity oil supply nozzle (4). The oil storage tank is equipped with a movable piston, which divides the interior of the oil storage tank into a lubricating oil chamber and a pneumatic chamber. The lubricating oil chamber is connected to the inlet and outlet of the oil storage tank, and the pneumatic chamber is connected to the bearing cavity sealing air pipe (1) through a throttle nozzle (2).

2. The emergency lubrication system for the bearing cavity of an aero-engine as described in claim 1, characterized in that, When the engine is running and in normal operation, the pressure of the bearing cavity oil supply pipe (3) is greater than the pressure of the bearing cavity sealing sump pipe (1). The lubricating oil overcomes the opening pressure of the one-way valve (5) and enters the oil reservoir, pushing the piston to move to store the lubricating oil.

3. The emergency lubrication system for the bearing cavity of an aero-engine as described in claim 1, characterized in that, When the pressure in the bearing cavity oil supply pipe (3) drops to less than the pressure in the bearing cavity sealing sump pipe (1) due to engine overrun or overload, the high-pressure gas in the bearing cavity sealing sump pipe (1) acts on the piston through the throttle nozzle (2), pushing the piston to pump the lubricating oil in the oil tank into the bearing cavity through the emergency oil supply nozzle (7).

4. The emergency lubrication system for the bearing cavity of an aero-engine as described in claim 1, characterized in that, The displacement stroke of the piston is matched with the volume of the oil reservoir, which is designed based on the preset lubricating oil interruption time and emergency oil supply.

5. The emergency lubrication system for the bearing cavity of an aero-engine as described in claim 1, characterized in that, The throttle nozzle (2) is configured to ensure that the pressure in the pneumatic chamber always meets the following condition: P bearing chamber oil supply pipe > P pneumatic chamber > P bearing chamber.

6. The emergency lubrication system for the bearing cavity of an aero-engine as described in claim 1, characterized in that, The one-way valve (5) is configured to prevent the lubricating oil in the oil reservoir from flowing back into the oil supply pipe (3) of the bearing cavity, and to remain closed during the lubricating oil interruption.

7. The emergency lubrication system for the bearing cavity of an aero-engine as described in claim 1, characterized in that, The auxiliary oil supply mechanism (6) is integrated and installed inside the bearing cavity.

8. The emergency lubrication system for the bearing cavity of an aero-engine as described in claim 1, characterized in that, During normal engine operation, the bearing cavity oil supply nozzle (4) and the emergency oil supply nozzle (7) supply oil to the bearing cavity simultaneously. The sum of the oil supply from the emergency oil supply nozzle (7) and the oil supply from the bearing cavity oil supply nozzle (4) is the total amount of lubricating oil required by the bearing cavity.

9. The emergency lubrication system for the bearing cavity of an aero-engine as described in claim 1, characterized in that, The cross-sectional area of ​​the piston is larger than the equivalent flow area of ​​the emergency oil supply nozzle (7) to ensure that the piston can pump out a sufficient amount of lubricating oil per unit time.

Images