Spaceflight turbine pump low-temperature bearing test loading device and loading method

Abstract

The invention relates to the technical field of bearing tests, in particular to a loading device and a loading method for a low-temperature bearing test of a spaceflight turbine pump. Comprising a test shaft shell, a test bearing A, an axial loading gland, an axial loading piston cylinder shell, an axial loading piston, a variable-diameter piston cylinder shell, a variable-diameter piston cylinder piston, a vaporizer, a test bearing B, a liquid nitrogen pipeline, a nitrogen pipeline and a hydraulic oil pipeline. Liquid nitrogen enters a test shaft shell from a liquid nitrogen pipeline to be fully cooled and then is discharged, the liquid nitrogen is converted into nitrogen through heat exchange of a vaporizer, the nitrogen is introduced into a variable-diameter piston cylinder shell through a nitrogen pipeline to push a variable-diameter piston cylinder piston to compress hydraulic oil, and the hydraulic oil is introduced into an axial loading piston cylinder shell to generate oil pressure to push an axial loading piston to move. The axial loading piston generates thrust on the axial loading gland to promote the axial loading gland to complete thrust loading on the test bearing, the electric cylinder is adopted to directly apply push-pull force load to the variable-diameter piston rod, load fluctuation is compensated, and stability of the test load is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of bearing testing, and in particular to a loading device and a loading method for a low-temperature bearing test of an aerospace turbo pump. Background Art

[0002] Low-temperature bearing testing is an important means of evaluating the performance of bearings in low-temperature environments. It mainly involves testing the operating stability, friction characteristics, load-bearing capacity, and life of bearings under low-temperature conditions.

[0003] To simulate the actual operating conditions of cryogenic bearings, liquid nitrogen is often used as the cryogenic medium for bearing testing. The bearing test chamber is a sealed structure, and liquid nitrogen circulates through the chamber's supply and return connections. The test simulates the operating pressure of the bearing in the turbo pump, so the chamber pressure is usually ≤5MPa during the test. During the test, the bearing heat generation is unstable, resulting in uneven vaporization of the liquid nitrogen inside the chamber. This leads to large fluctuations in the chamber pressure, which directly causes large fluctuations in the vaporized nitrogen pressure, which can easily lead to unstable loading. Summary of the Invention

[0004] In order to solve the technical problems such as unstable bearing heating during the existing low-temperature bearing test, uneven liquid nitrogen vaporization inside the cavity, large cavity pressure fluctuations, large nitrogen pressure fluctuations after vaporization, and easy loading instability, the present invention proposes an aerospace turbopump low-temperature bearing test loading device to solve the above problems.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a space turbine pump low-temperature bearing test loading device, including a test shaft housing, a test bearing A, an axial loading cover, an axial loading piston cylinder housing, an axial loading piston, a variable diameter piston cylinder housing, a variable diameter piston cylinder piston, a vaporizer, a test bearing B, a liquid nitrogen pipeline, a nitrogen pipeline and a hydraulic oil pipeline; the upper and lower ends of the vaporizer are connected to the test shaft housing and the variable diameter piston cylinder housing through the liquid nitrogen pipeline and the nitrogen pipeline respectively, and the test bearing A and the test bearing B are relatively installed on both sides of the interior of the test shaft housing. The liquid nitrogen enters the test shaft housing from the liquid nitrogen pipeline and is fully cooled and then discharged. It is converted into nitrogen through heat exchange in the vaporizer and is passed into the variable diameter piston cylinder housing through the nitrogen pipeline, pushing the variable diameter piston cylinder piston to compress the hydraulic oil at the bottom of the variable diameter piston cylinder housing. The hydraulic oil is passed into the interior of the axial loading piston cylinder housing to generate oil pressure to push the axial loading piston to move. The axial loading piston generates thrust on the axial loading cover, prompting the axial loading cover to complete thrust loading on the test bearing A and the test bearing B.

[0006] As a further optimization solution for the above-mentioned aerospace turbopump cryogenic bearing test loading device, the test shaft housing is provided with liquid inlet and outlet for connecting to the liquid nitrogen pipeline, and a test shaft cavity pressure sensor is provided on the liquid nitrogen pipeline outlet.

[0007] As a further optimization solution for the above-mentioned aerospace turbopump cryogenic bearing test loading device, a variable-diameter piston cylinder gas phase pressure sensor is provided on the nitrogen pipeline.

[0008] As a further optimization scheme of the above-mentioned aerospace turbopump low-temperature bearing test loading device, the test bearing A and the test bearing B are both sleeved and installed on the test shaft, the test shaft and the test shaft housing are clearance-fitted and can move relative to each other in the test shaft housing.

[0009] As a further optimization scheme of the above-mentioned aerospace turbine pump low-temperature bearing test loading device, the axial loading cover is arranged on one side of the outer ring end face of the test bearing B, the axial loading cover is clearance-matched with the test shaft housing, and can be relatively displaced within the test shaft housing.

[0010] As a further optimization solution of the above-mentioned aerospace turbopump cryogenic bearing test loading device, the axial loading piston and the axial loading piston cylinder housing are clearance-matched and can move relatively within the axial loading piston cylinder housing.

[0011] As a further optimization solution of the above-mentioned aerospace turbopump cryogenic bearing test loading device, the variable diameter piston cylinder piston is arranged in the variable diameter piston cylinder housing and has a clearance fit with the variable diameter piston cylinder housing.

[0012] As a further optimization scheme of the above-mentioned aerospace turbine pump low-temperature bearing test loading device, the two ends of the hydraulic oil pipeline are respectively connected to the bottom flange of the variable diameter piston cylinder and the end face flange of the axial loading piston cylinder, and an axial loading piston cylinder pressure sensor is provided on the hydraulic oil pipeline.

[0013] As a further optimization scheme of the above-mentioned aerospace turbine pump low-temperature bearing test loading device, an electric cylinder is arranged above the variable diameter piston cylinder housing, the piston rod of the electric cylinder extends into the variable diameter piston cylinder housing and abuts against the top end of the variable diameter piston cylinder piston, and an electric cylinder thrust sensor is arranged on the piston rod of the electric cylinder.

[0014] A loading method for aerospace turbopump cryogenic bearing test comprises the following steps: S, liquid nitrogen is introduced into the test shaft housing from the liquid inlets arranged on the left and right sides of the test shaft housing to fully cool the inner and outer rings of the test bearings A and B inside the housing, and then discharged from the liquid outlet; S, the liquid nitrogen discharged from step S passes through the test shaft cavity pressure sensor, and the test shaft cavity pressure sensor monitors the internal pressure of the test shaft housing; S, the liquid nitrogen passing through the test shaft cavity pressure sensor enters the vaporizer for heat exchange, and the liquid nitrogen is converted into nitrogen gas, which is then passed through the variable diameter piston cylinder gas phase pressure sensor into the variable diameter piston cylinder housing; S, the piston rod of the electric cylinder directly abuts against the piston of the variable piston cylinder, and together with the nitrogen at the top of the variable piston cylinder housing, it generates pressure on the piston of the variable piston cylinder, pushing the piston of the variable piston cylinder downward and compressing the hydraulic oil at the bottom of the variable piston cylinder housing; S, the hydraulic oil at the bottom of the variable diameter piston cylinder housing is compressed and enters the axial loading piston cylinder housing, and pushes the axial loading piston to move. The axial loading piston generates thrust on the axial loading gland, prompting the axial loading gland to complete thrust loading on the test bearings A and B.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. When the axial loading piston of the present invention is working, the interior of the loading piston cylinder is filled with hydraulic oil, the exterior of the loading piston is connected to the test cavity, the interior of the test cavity is filled with liquid nitrogen, the liquid nitrogen contacts the outer surface of the loading piston, and the hydraulic oil contacts the inner surface of the loading piston. The liquid nitrogen and the hydraulic oil exchange heat through the piston. During the heat exchange process, the liquid nitrogen rapidly vaporizes to form an air film on the outer surface of the piston. The air film can support the outer surface of the loading piston, reduce the working friction of the piston, and improve the accuracy of the test loading.

[0016] 2. During the test, the bearing heat generation was unstable, resulting in uneven vaporization of the liquid nitrogen inside the cavity. This led to large pressure fluctuations in the cavity, which directly caused large pressure fluctuations in the vaporized nitrogen and easily led to unstable loading. To address this issue, an electric cylinder was used to directly apply push and pull forces to the variable-diameter piston rod, compensating for load fluctuations and ensuring stable test loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the cross-sectional structure of the present invention; Figure 2 This is a schematic diagram of the liquid nitrogen, nitrogen gas and hydraulic oil circuits; Figure 3 Schematic diagram of the pressure and pressure position of each part; Markings in the figure: 1. Test shaft, 2. Test shaft sealing ring, 3. Test shaft housing, 4. Test bearing A, 5. Axially loaded pressure cap, 6. Test shaft housing flange sealing ring, 7. Test shaft housing flange, 8. Axially loaded piston cylinder housing sealing ring, 9. Axially loaded piston cylinder housing, 10. Axially loaded piston sealing ring, 11. Axially loaded piston, 12. Axially loaded piston cylinder end face flange, 13. Axially loaded piston cylinder pressure sensor, 14. Variable diameter piston cylinder bottom flange, 15. Variable diameter piston cylinder housing, 16. Variable diameter piston cylinder piston small end sealing ring, 17. Variable diameter piston cylinder piston, 18. Variable diameter piston cylinder piston large end sealing ring, 19. Variable diameter piston cylinder top flange, 20. Variable diameter piston cylinder top flange sealing ring, 21. Electric cylinder thrust sensor, 22. Electric cylinder, 23. Variable diameter piston cylinder gas phase pressure sensor, 24. Carburetor, 25. Test shaft cavity pressure sensor, 26. Test bearing B. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0019] like Figure 1 As shown, a test loading device for a low-temperature bearing of an aerospace turbopump includes a test shaft housing 3, a test bearing A4, an axial loading gland 5, an axial loading piston cylinder housing 9, an axial loading piston 11, a variable-diameter piston cylinder housing 15, a variable-diameter piston cylinder piston 17, a vaporizer 24, a test bearing B26, a liquid nitrogen pipeline, a nitrogen pipeline and a hydraulic oil pipeline; the test shaft housing 3 is provided with a liquid inlet and outlet for connecting to the liquid nitrogen pipeline, and a test shaft cavity pressure sensor 25 is provided on the liquid outlet of the liquid nitrogen pipeline; a variable-diameter piston cylinder gas phase pressure sensor 23 is provided on the nitrogen pipeline; the test bearing A4 and the test bearing B26 are both sleeved and installed on the test shaft 1, and the test shaft 1 is clearance-fitted with the test shaft housing 3 and can move relative to each other in the test shaft housing 3; the upper and lower ends of the vaporizer 24 are connected to the test shaft housing 3 and the variable-diameter piston cylinder housing 15 through the liquid nitrogen pipeline and the nitrogen pipeline respectively, and the test bearing A4 and the test bearing B26 are relatively installed on both sides of the interior of the test shaft housing 3.

[0020] The axial loading cover 5 is disposed on one side of the outer ring end face of the test bearing B26. The axial loading cover 5 has a clearance fit with the test shaft housing 3 and is relatively displaceable within the test shaft housing 3. The axial loading piston 11 has a clearance fit with the axial loading piston cylinder housing 9 and is relatively displaceable within the axial loading piston cylinder housing 9. The variable diameter piston 17 is disposed within the variable diameter piston cylinder housing 15 and has a clearance fit with the variable diameter piston cylinder housing 15.

[0021] The two ends of the hydraulic oil pipeline are respectively connected to the bottom flange 14 of the variable-diameter piston cylinder and the end flange 12 of the axially loaded piston cylinder. An axially loaded piston cylinder pressure sensor 13 is provided on the hydraulic oil pipeline.

[0022] An electric cylinder 22 is provided above the variable-diameter piston cylinder housing 15 , and a piston rod of the electric cylinder 22 extends into the variable-diameter piston cylinder housing 15 and abuts against the top of the variable-diameter piston cylinder piston 17 . An electric cylinder thrust sensor 21 is provided on the piston rod of the electric cylinder 22 .

[0023] like Figure 2 and Figure 3 As shown, a loading method for a low-temperature bearing test of an aerospace turbopump includes the following steps: S1, liquid nitrogen is introduced into the test shaft housing 3 through the liquid inlets provided on the left and right sides of the test shaft housing 3, fully cooling the inner and outer rings of the test bearings A4 and B26 inside the housing, and then discharged through the liquid outlet; S2, the liquid nitrogen discharged from step S1 passes through the test shaft cavity pressure sensor 25, and the test shaft cavity pressure sensor 25 monitors the internal pressure of the test shaft housing 3; S3, the liquid nitrogen passing through the test shaft cavity pressure sensor 25 enters the vaporizer 24 for heat exchange, and the liquid nitrogen is converted into nitrogen gas, which is then passed through the variable diameter piston cylinder gas phase pressure sensor 23 into the variable diameter piston cylinder housing 15; In step S4, the piston rod of the electric cylinder 22 directly abuts against the variable piston cylinder piston 17, and together with the nitrogen at the top of the variable piston cylinder housing 15, generates pressure on the variable piston cylinder piston 17, pushing the variable piston cylinder piston 17 downward and compressing the hydraulic oil at the bottom of the variable piston cylinder housing 15; S5, the hydraulic oil at the bottom of the variable diameter piston cylinder housing 15 is compressed and enters the axial loading piston cylinder housing 9, and pushes the axial loading piston 11 to move. The axial loading piston 11 generates thrust on the axial loading cover 5, prompting the axial loading cover 5 to complete thrust loading on the test bearing A4 and the test bearing B26.

[0024] exist Figure 1 In the figure, letter A represents the diameter of the variable diameter piston cylinder, letter B represents the diameter of the piston rod of the variable diameter piston cylinder, letter C represents the diameter of the axially loaded piston cylinder, and letter D represents the diameter of the test shaft. The discharged liquid nitrogen first passes through the pressure gauge P3 (test shaft cavity pressure), and then passes through the tee. A part of it is diverted to the vaporizer 24, and is vaporized into nitrogen through the vaporizer 24. The nitrogen pressure is about 1~5MPa. It passes through the pressure gauge P1 (gas phase pressure of the variable diameter piston cylinder) and finally enters the variable diameter piston cylinder. The output hydraulic oil is pressurized by the variable diameter piston rod. After pressurization, the hydraulic oil passes through P2 (test loading cylinder pressure) and enters the test loading cylinder.

[0025] The P3 pressure is the pressure in the test shaft cavity. During the test, the bearing generates unstable heat, resulting in uneven vaporization of the liquid nitrogen inside the cavity. This causes large fluctuations in the P3 cavity pressure, which directly leads to large fluctuations in the nitrogen pressure P1 after vaporization, which can easily lead to unstable loading. To address this problem, an electric cylinder is used to directly apply push and pull loads to the variable diameter piston rod to compensate for load fluctuations.

[0026] The thrust generated by the cavity pressure P3 on the test bearing A is expressed as: , The thrust generated by the pressure P1 at the large end of the variable diameter piston cylinder is expressed as: , The pressure P2 at the small end of the variable diameter piston cylinder is expressed as: , Axial loading piston thrust F 轴向加载活塞 Expressed as: , Actual force F on test bearing A 试验轴承A Expressed as: , Actual force F on test bearing B 试验轴承B Expressed as: .

[0027] Based on the above calculations, the actual thrust borne by the test bearing A during the test can be obtained. At the same time, under the condition of unstable load, the specific value of the compensation force required by the F electric cylinder can be calculated through the formula to compensate for the load and ensure the stability of the test load.

[0028] The preferred specific implementation modes and embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes and embodiments. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the concept of the present invention.

Claims

1. A loading device for aerospace turbopump cryogenic bearing test, characterized by: The invention comprises a test shaft housing (3), a test bearing A (4), an axial loading cover (5), an axial loading piston cylinder housing (9), an axial loading piston (11), a variable diameter piston cylinder housing (15), a variable diameter piston cylinder piston (17), a vaporizer (24), a test bearing B (26), a liquid nitrogen pipeline, a nitrogen pipeline and a hydraulic oil pipeline; the upper and lower ends of the vaporizer (24) are respectively connected to the test shaft housing (3) and the variable diameter piston cylinder housing (15) through the liquid nitrogen pipeline and the nitrogen pipeline, and the test bearing A (4) and the test bearing B (26) are relatively installed on both sides of the interior of the test shaft housing (3). Liquid nitrogen enters the test shaft housing (3) from the liquid nitrogen pipeline and is discharged after being fully cooled. It is converted into nitrogen through heat exchange in the vaporizer (24) and is passed into the variable-diameter piston cylinder housing (15) through the nitrogen pipeline, pushing the variable-diameter piston cylinder piston (17) to compress the hydraulic oil at the bottom of the variable-diameter piston cylinder housing (15). The hydraulic oil is passed into the axial loading piston cylinder housing (9) to generate oil pressure to push the axial loading piston (11) to move. The axial loading piston (11) generates thrust on the axial loading cover (5), prompting the axial loading cover (5) to complete thrust loading on the test bearing A (4) and the test bearing B (26).

2. The aerospace turbopump cryogenic bearing test loading device according to claim 1, characterized in that: The test shaft housing (3) is provided with a liquid inlet and a liquid outlet for connecting to a liquid nitrogen pipeline, and a test shaft cavity pressure sensor (25) is provided on the liquid outlet of the liquid nitrogen pipeline.

3. The aerospace turbopump cryogenic bearing test loading device according to claim 1, characterized in that: A variable-diameter piston cylinder gas phase pressure sensor (23) is provided on the nitrogen pipeline.

4. The aerospace turbopump cryogenic bearing test loading device according to claim 1, characterized in that: The test bearing A (4) and the test bearing B (26) are both sleeved and mounted on the test shaft (1). The test shaft (1) and the test shaft housing (3) are clearance-matched and can be relatively displaced within the test shaft housing (3).

5. The aerospace turbopump cryogenic bearing test loading device according to claim 1, characterized in that: The axial loading cover (5) is arranged on one side of the outer ring end face of the test bearing B (26). The axial loading cover (5) is clearance-matched with the test shaft housing (3) and can be relatively displaced within the test shaft housing (3).

6. The aerospace turbopump cryogenic bearing test loading device according to claim 1, characterized in that: The axial loading piston (11) is clearance-matched with the axial loading piston cylinder housing (9) and can be relatively displaced within the axial loading piston cylinder housing (9).

7. The aerospace turbopump cryogenic bearing test loading device according to claim 1, characterized in that: The variable diameter piston cylinder piston (17) is arranged in the variable diameter piston cylinder housing (15) and is clearance-matched with the variable diameter piston cylinder housing (15).

8. The aerospace turbopump cryogenic bearing test loading device according to claim 1, characterized in that: The two ends of the hydraulic oil pipeline are respectively connected to the variable-diameter piston cylinder bottom flange (14) and the axially loaded piston cylinder end face flange (12), and an axially loaded piston cylinder pressure sensor (13) is provided on the hydraulic oil pipeline.

9. The aerospace turbopump cryogenic bearing test loading device according to any one of claims 1 to 8, characterized in that: An electric cylinder (22) is provided above the variable-diameter piston cylinder housing (15); a piston rod of the electric cylinder (22) extends into the variable-diameter piston cylinder housing (15) and abuts against the top end of the variable-diameter piston cylinder piston (17); and an electric cylinder thrust sensor (21) is provided on the piston rod of the electric cylinder (22).

10. A loading method for aerospace turbopump cryogenic bearing test, characterized by: The following steps are included: S1, liquid nitrogen is introduced into the test shaft housing (3) from the liquid inlets provided on the left and right sides of the test shaft housing (3), and the inner and outer rings of the test bearing A (4) and the test bearing B (26) inside the housing are fully cooled, and the liquid nitrogen is discharged from the liquid outlet; S2, the liquid nitrogen discharged from step S1 passes through the test shaft cavity pressure sensor (25), and the test shaft cavity pressure sensor (25) monitors the internal pressure of the test shaft housing (3); S3, the liquid nitrogen passing through the test shaft cavity pressure sensor (25) enters the vaporizer (24) for heat exchange, and the liquid nitrogen is converted into nitrogen gas, which is then passed through the variable diameter piston cylinder gas phase pressure sensor (23) into the variable diameter piston cylinder housing (15); S4, the piston rod of the electric cylinder (22) directly abuts against the variable-diameter piston cylinder piston (17), and together with the nitrogen at the top of the variable-diameter piston cylinder housing (15), generates pressure on the variable-diameter piston cylinder piston (17), pushing the variable-diameter piston cylinder piston (17) downward, compressing the hydraulic oil at the bottom of the variable-diameter piston cylinder housing (15); S5, the hydraulic oil at the bottom of the variable diameter piston cylinder housing (15) is compressed and enters the axial loading piston cylinder housing (9), and pushes the axial loading piston (11) to move. The axial loading piston (11) generates thrust on the axial loading pressure cover (5), prompting the axial loading pressure cover (5) to complete thrust loading on the test bearing A (4) and the test bearing B (26).

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