Oil mist separation device for non-contact sealing of gearbox under internal and external pressure difference environment

Abstract

A non-contact sealed oil mist separation device for a gearbox under internal and external pressure difference conditions includes a high-speed transfer gearbox connected to the aero-engine via a drive shaft, located in the high-altitude simulation cabin of an aero-engine. The output shaft of the gearbox is connected to a dynamometer operating under atmospheric pressure outside the cabin. A non-contact sealed oil mist separation device, consisting of an oil tank and a motor-driven oil pump, is installed in the gearbox's lubricating oil circulation circuit. A vent cap is installed on the oil tank. An oil mist discharge pipe for the gearbox vent cap is connected between the flange interface at the top of the gearbox and the oil return port of the oil tank. An oil mist discharge pipe for the gearbox input end sealing oil mist collection cover is connected between the oil return port of the oil tank. An oil tank balance oil outlet pipe is connected between the gearbox torque measuring flange cover and the oil return port of the oil tank. An oil mist separation oil tank collecting lubricating oil discharge pipe is connected between the filter at the top of the gearbox and the oil pump outlet.

Description

Technical Field

[0001] The invention relates to the field of high-altitude simulation tests for aircraft engines, and in particular to a non-contact sealed oil mist separation device for a high-speed transfer gearbox used in a high-altitude simulation test bench. Background Art

[0002] The aircraft engine high-altitude simulation test bench is a ground test equipment that can simulate the altitude, speed and other conditions of the engine in the air. It is an indispensable and effective test method for the development of advanced aircraft engines and propulsion systems. The test bench uses a high-speed transfer gearbox to reduce speed and test the performance index data of the aircraft engine. It is a key equipment in the transmission system of the aircraft engine high-altitude simulation test cabin. Its operating performance directly affects the data collection of the aircraft engine high-altitude simulation test.

[0003] In order to simulate the real operating environment of aircraft engines, the test bench needs to work for a long time under changing pneumatic pressure and temperature environment. Especially when simulating the air pressure conditions at an altitude of 7,000 meters, the air pressure outside the simulated test cabin is 101325Pa (one atmosphere), and the simulated air pressure inside the test cabin is 41043Pa, which is only 41% of the atmospheric pressure outside the cabin. At the same time, the high-speed transfer gearbox is connected to the lubrication oil station outside the cabin through the lubrication oil pipeline, resulting in a huge air pressure difference between the inside and outside of the gearbox input end seal. This unconventional working state makes the lubrication and sealing conditions of the high-speed transfer gearbox very bad. For this reason, good lubrication performance and sealing performance have become one of the important indicators to measure the working performance of the high-speed transfer gearbox in the high-altitude simulation cabin.

[0004] For high-speed gearboxes, common lubrication methods include oil immersion lubrication and pressure lubrication. Generally, when the linear speed of the gear is greater than 12m / s, pressure lubrication should be considered. Pressure lubrication can not only fully lubricate the transmission parts in the box, but also better cool the heated lubricating oil during the circulation process from the oil tank to the gearbox. For high-speed transfer gearboxes used in high-altitude simulation test benches, whose gear transmission linear speed is as high as 127m / s, pressure lubrication is a more reliable lubrication method.

[0005] On the aircraft engine high-altitude simulation test bench, the high-speed transfer gearbox is connected to the aircraft engine through a transmission shaft and arranged together in the high-altitude simulation cabin. The output shaft of the gearbox is connected to the dynamometer at the atmospheric pressure state outside the cabin, and is connected to the lubricating oil station outside the cabin through the lubricating oil pipeline. Therefore, when the experimental cabin simulates the high-altitude environment, there is a huge air pressure difference between the inside and outside of the seal at the input end of the gearbox, which easily leads to lubricating oil leakage at the input end of the gearbox when a non-contact oil seal is used. On the other hand, during the high-speed operation of the gears, the lubricating oil in the inner cavity of the gearbox case is impacted by the high-speed gear meshing and the lubricating oil is beaten into an oil mist state. At the same time, the gear meshing impact on the lubricating oil generates a large amount of heat energy, which expands the air in the cavity and causes the inner cavity of the gearbox to be positively pressurized relative to the outside of the case. When there are pressure strips inside and outside the gearbox, the oil mist generated in the gearbox will also be sucked out from the breathable cap of the gearbox due to the negative pressure outside the case. If the breathable cap is closed, a pressure difference will be formed between the positive air pressure in the inner cavity of the gearbox due to high-speed operation and the atmospheric pressure outside the cabin, causing the lubricating oil of the non-contact seal at the output end of the gearbox to leak.

[0006] At present, there are two types of shaft end seals for high-speed gearboxes using pressure lubrication: contact and non-contact. Since the selection limit of contact seals is much lower than the input shaft speed of the test bench gearbox, it is not suitable for high-speed gearboxes. Moreover, for the high-speed transfer gearbox of the high-altitude simulation test bench for aircraft engines, the use of non-contact seals alone, or the combination of non-contact seals and pneumatic seals, cannot fundamentally solve the problem of lubricating oil leakage caused by the huge air pressure difference between the inside and outside of the gearbox. Therefore, it is necessary to study an oil mist separation device that realizes internal circulation with the help of the gearbox lubrication oil circuit, overcome the influence of the high pressure difference between the inside and outside of the gearbox, and solve the problem of lubricating oil leakage at the shaft end of the transmission shaft using non-contact seals. Summary of the invention

[0007] The purpose of the present invention is to provide a non-contact sealed oil mist separation device for gearboxes under internal and external pressure difference environment in order to address the deficiencies in the above-mentioned prior art. The device of the present invention is aimed at the situation where the shaft end of the high-speed gearbox adopts non-contact sealing. Based on the negative pressure environment of the high-speed transfer gearbox in the high-altitude simulation cabin, an oil mist separation device is used in the lubricating oil circuit connecting the gearbox and the lubricating oil station, and an internal circulation of part of the lubricating oil is established between the gearbox and the oil mist separation device, so as to solve the problem of lubricating oil leakage at the shaft end of the high-speed transfer gearbox in the high-altitude test cabin of the aircraft engine.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] 1. Establish an external circulation of lubricating oil between the gearbox and the lubricating oil station:

[0010] With the help of the thin oil station, the lubricating oil is forced into the gear box, and the return oil pump is used to force the oil back, overcoming the influence of the vacuum environment in the test chamber and establishing an external circulation of lubricating oil between the gear box and the lubricating oil station.

[0011] 2. Design and build an oil mist separation device, and make the air pressure in the device communicate with the negative pressure in the high-altitude cabin:

[0012] An oil mist separation device is designed and built. Through the breathable cap on the oil tank in the device, the inside of the oil tank is connected to the negative pressure in the high-altitude simulation cabin. On this basis, the lubricating oil entering the oil tank is circulated out through an oil pump driven by a motor installed on the oil tank.

[0013] 3. Establish internal circulation of lubricating oil between the gearbox and the oil mist separator:

[0014] 1) First, change the breathable cap on the top of the high-speed transfer gearbox to a suitable transfer flange interface, and connect it to the oil return port of the oil tank of the oil mist separation device through a pipeline. Use the negative pressure inside the oil tank in the separation device to extract the oil mist generated during the high-speed operation of the gears in the gearbox body cavity and introduce it into the oil tank;

[0015] 2) Add a protective cover on the outside of the high-speed shaft seal at the input end of the gearbox to collect the lubricating oil sucked out from the sealing gap due to the internal and external pressure difference at the non-contact seal at the end of the transmission shaft, and connect it to the oil return port of the oil tank of the oil mist separation device through a pipeline. Use the negative pressure inside the oil tank in the separation device to extract the lubricating oil in the protective cover and introduce it into the oil tank;

[0016] 3) A corresponding reflux flange interface is provided on the high-speed transfer gearbox, and is connected to the oil tank outlet of the oil mist separation device through a pipeline. The lubricating oil condensed and filtered by the oil mist separation device generates power through the oil pump and flows back to the gearbox from the oil tank.

[0017] Further, the specific technical measures to implement the present invention are as follows:

[0018] The non-contact sealed oil mist separation device for the gear box under the internal and external pressure difference environment of the present invention comprises a high-speed transfer gear box arranged in the high-altitude simulation cabin of the aircraft engine and connected to the aircraft engine through a transmission shaft; the output shaft of the high-speed transfer gear box is connected to a dynamometer under the atmospheric pressure state on the ground outside the cabin, that is, the lubricating oil is forcibly pressed into the interior of the gear box with the help of a lubricating oil station, and a return oil pump is used to force the oil return, so as to overcome the influence of the vacuum environment in the test cabin and establish a lubricating oil circulation oil circuit between the gear box and the lubricating oil station; a non-contact sealed oil mist separation device consisting of an oil tank and an oil pump driven by a motor is arranged between the lubricating oil circulation oil circuit of the high-speed transfer gear box; an oil indicator and a breathable cap for keeping the internal pressure consistent with the negative pressure in the high-altitude simulation cabin are arranged on the oil tank; an oil mist discharge pipe of the gear box breathable cap is connected between the flange interface on the upper part of the high-speed transfer gear box and the oil return port of the oil tank, The negative pressure of the internal part is used to extract the oil mist generated during the high-speed operation of the gears in the inner cavity of the high-speed transfer gearbox and introduce it into the oil tank; an oil mist discharge pipe 10" of the gearbox input end sealing oil mist collection shield is connected between the input end sealing oil mist collection shield of the high-speed transfer gearbox and the oil return port of the oil tank, which is used to drain the lubricating oil leaked from the non-contact seal of the high-speed transfer gearbox due to the internal and external pressure difference into the oil tank; an oil tank balance oil volume oil outlet pipe is connected between the torque measuring flange shield of the high-speed transfer gearbox and the oil return port of the oil tank, which is used to guide a certain amount of lubricating oil in the gearbox into the oil tank, prevent the oil pump from being drained, and ensure the reliable operation of the lubricating oil internal circulation between the gearbox and the oil mist separation device; an oil mist separation tank collection lubricating oil discharge pipe is connected between the filter on the upper part of the high-speed transfer gearbox and the oil pump outlet located in the oil tank, and the lubricating oil in the oil tank is forced to be drawn back to the high-speed transfer gearbox by the motor-driven oil pump.

[0019] The lubricating oil circulation oil circuit of the high-speed transfer gear box is communicated with the lubricating oil station outside the cabin through a lubricating oil circuit pipeline.

[0020] Furthermore, the specific measures of the present invention to ensure reliable operation of the internal circulation of lubricating oil between the high-speed transfer gearbox and the oil mist separation device are as follows:

[0021] In the high-altitude simulation test cabin of the aircraft engine, the oil mist in the inner cavity of the gear box body drawn out by the negative pressure inside the oil tank in the oil mist separation device cannot be quantified and calculated, and the oil tank oil pump in the oil mist separation device cannot be accurately selected. This may cause the oil pump to run dry during the use of the oil mist separation device, resulting in failure of the oil mist separation device, and the internal circulation of the lubricating oil between the gear box and the oil mist separation device cannot operate reliably. Based on this, an oil tank balance oil outlet pipe is set in the gear box to lead a certain amount of lubricating oil in the gear box to the oil tank of the oil mist separation device, so as to calculate and select the oil tank capacity and oil pump model, prevent the oil pump from being drained, and ensure the reliable operation of the internal circulation of the lubricating oil between the gear box and the oil mist separation device.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The high-speed gearbox using a non-contact seal oil mist separation device successfully solves the problem that the lubricating oil in the gearbox cavity is sucked out from the high-speed input end seal under the conditions of positive pressure in the gearbox cavity and negative pressure outside the input end high-speed seal.

[0024] 2. The high-speed gearbox using the oil mist separation device can be tested under any pressure difference environment.

[0025] 3. The cost of the non-contact sealed oil mist separation device is only one-fifteenth of that of the contact fingertip seal, whose technology is not yet mature.

[0026] 4. Compared with the contact fingertip seal, the oil mist separation device does not have the wear caused by high-speed operation, so there is no problem with operating life.

[0027] 5. Compared with the contact fingertip seal, the oil mist separation device does not have the wear caused by high-speed operation, so there is no wear problem on the gear shaft during high-speed operation.

[0028] 6. The non-contact sealed oil mist separation device provides a new reliable, convenient and cost-saving option for high-speed gearboxes under the condition of pressure difference between the inner cavity of the gearbox and the external environment, and provides a new idea for the development of similar gearboxes. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The overall structure of the high-altitude simulation test bench.

[0030] Figure 1 Sequence number: 1′ high-speed transfer gearbox, 2′ non-contact sealed oil mist separation device, 3′ aircraft engine high altitude simulation cabin, 4′ aircraft engine under test, 5′ dynamometer, 6′ lubrication main oil station.

[0031] Figure 2Front view of the internal circulation of lubricating oil between the gearbox and the oil mist separator.

[0032] Figure 3 yes Figure 2 Left view of .

[0033] Figure 2 , 3 Serial number: 1' high-speed transfer gearbox, 2" oil tank, 3" motor, 4" oil pump, 5" oil indicator, 6" filter, 7" oil tank breather cap, 8" gearbox breather cap oil mist discharge pipe, 9" gearbox input end sealed oil mist collection shield, 10" gearbox input end sealed oil mist collection shield oil mist discharge pipe, 11" oil tank balance oil volume outlet pipe, 12" torque measuring flange shield, 13" oil mist separation tank collects lubricating oil discharge pipe.

[0034] Figure 4 Front view of the oil mist separator.

[0035] Figure 5 yes Figure 4 Top view of the .

[0036] Figure 4 , 5 Serial number: 2" oil tank, 3" motor, 4" oil pump, 5" oil indicator, 7" oil tank breather cap. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with embodiments (attached drawings):

[0038] like Figures 1 to 5 As shown, the present invention provides an oil mist separation device for the situation where the shaft end of the high-speed gearbox adopts non-contact sealing under the internal and external pressure difference environment, and establishes a closed internal circulation of part of the lubricating oil between the gearbox and the oil mist separation device to solve the problem of lubricating oil leakage at the shaft end of the high-speed transfer gearbox using non-contact sealing in the high-altitude test chamber of the aircraft engine. The specific implementation method is as follows:

[0039] 1. Under the internal and external pressure difference environment, establish the lubricating oil circulation circuit of the high-speed gearbox:

[0040] See also Figure 1 On the aircraft engine high altitude simulation test bench, the high speed transfer gearbox 1' is connected to the aircraft engine 4' through a transmission shaft, and is arranged together in the aircraft engine high altitude simulation cabin 3'; the output shaft of the high speed transfer gearbox 1' is connected to the dynamometer 5' at the atmospheric pressure state outside the cabin, and is communicated with the lubricating oil station 6' outside the cabin through the lubricating oil pipeline. With the help of the lubricating oil station 6', the lubricating oil is forcibly pressed into the gearbox, and the return oil pump is used to force the oil to return, so as to overcome the influence of the vacuum environment in the test cabin, and establish a lubricating oil circulation oil circuit between the gearbox and the lubricating oil station.

[0041] 2. Build an oil mist separation device:

[0042] See also Figure 2~Figure 5 A non-contact sealed oil mist separation device 2' is arranged between the lubricating oil circulation oil circuit of the high-speed transfer gearbox 1', and the non-contact sealed oil mist separation device 2' comprises an oil tank 2", an oil pump 4" located in the oil tank and driven by a motor 3", an oil indicator 5" arranged on the oil tank, an oil tank breather cap 7" and an oil tank bracket; the breather cap 7" arranged on the oil tank 2" can make the pressure inside the oil tank 2" consistent with the negative pressure in the high-altitude simulation cabin. The oil pump 4" driven by the motor 3" can force the lubricating oil entering the oil tank to circulate out.

[0043] 3. Establish an internal circulation oil circuit for lubricating oil between the gearbox and the oil mist separator:

[0044] See also Figure 2~Figure 5 One end of the oil mist discharge pipe 8" of the gearbox breathable cap is connected to the flange interface on the upper part of the high-speed transfer gearbox 1', and the other end is connected to the oil return port of the oil tank 2" of the oil mist separation device. The negative pressure inside the oil tank in the separation device is used to extract the oil mist generated during the high-speed operation of the gears in the inner cavity of the high-speed transfer gearbox 1' and introduce it into the oil tank 2". One end of the oil mist discharge pipe 10" of the gearbox input end sealed oil mist collection shield is connected to the gearbox input end sealed oil mist collection shield 9", and the other end is connected to the oil return port of the oil tank 2", so that the lubricating oil leaked from the non-contact seal of the high-speed transfer gearbox 1" due to the internal and external pressure difference is drained to the oil tank 2". One end of the oil tank balance oil outlet pipe 11" is connected to the high-speed transfer gearbox torque measuring flange shield 12", and the other end is connected to the oil return port of the oil tank 2", so as to lead a certain amount of lubricating oil in the high-speed transfer gearbox 1' to the oil tank 2' of the oil mist separation device to prevent the oil pump from being drained, thereby ensuring the reliable operation of the lubricating oil internal circulation between the gearbox and the oil mist separation device; one end of the oil mist separation tank lubricating oil collection pipe 13" is connected to the oil outlet of the oil tank 2', and the other end is connected to the filter 6' on the upper part of the high-speed transfer gearbox 1', and the motor 3' drives the oil pump 4' to forcibly pump the lubricating oil in the oil tank 2' back to the high-speed transfer gearbox 1'.

Claims

1. A non-contact sealed oil mist separation device for a gear box under an internal and external pressure difference environment, characterized in that: It includes a high-speed transfer gearbox arranged in an aero-engine high-altitude simulation cabin and connected to the aero-engine through a transmission shaft; the output shaft of the high-speed transfer gearbox is connected to a dynamometer under atmospheric pressure on the ground outside the cabin; a non-contact sealed oil mist separation device consisting of an oil tank and an oil pump driven by a motor is arranged between the lubricating oil circulation oil circuit of the high-speed transfer gearbox; an oil indicator and a breathable cap for keeping the internal pressure consistent with the negative pressure in the high-altitude simulation cabin are arranged on the oil tank; an oil mist discharge pipe of the gearbox breathable cap is connected between the flange interface on the upper part of the high-speed transfer gearbox and the oil return port of the oil tank; an oil mist discharge pipe of the gearbox input end sealed oil mist collection shield is connected between the input end sealed oil mist collection shield of the high-speed transfer gearbox and the oil return port of the oil tank; an oil tank balance oil volume oil outlet pipe is connected between the torque measuring flange shield of the high-speed transfer gearbox and the oil return port of the oil tank; an oil mist separation oil tank collection lubricating oil discharge pipe is connected between the filter on the upper part of the high-speed transfer gearbox and the oil pump outlet located in the oil tank.

2. The non-contact sealed oil mist separation device for a gear box under an internal and external pressure difference environment according to claim 1, characterized in that: The lubricating oil circulation oil circuit of the high-speed transfer gear box is communicated with the lubricating oil station outside the cabin through a lubricating oil circuit pipeline.

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